Why are chickens passive when their eggs are taken?

Why are chickens passive when their eggs are taken?

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Most species don't seem enthusiastic when their eggs are taken, yet on farms with domesticated hens, they seem more passive when their eggs are harvested. Why does this occur?

The Dark Side of Chicken Keeping

Chickens are are getting more popular every day, with their hysterical antics and the delicious fresh eggs what not to love? I&rsquom here to burst your bubble and tell you all the things that can (and probably will) go wrong.

Before we get into the nitty-gritty and potentially gruesome heart of this post let me say this: I love my chickens. I will always have chickens.

This post has sat in my drafts for over 2 years because no one talks about this stuff and I didn&rsquot want to be the Negative Nancy of Chicken Husbandry.

So here we go, the dark side of chicken keeping.

This is in no way intended to dissuade you from owning chickens. BUT there are two sides to every coin and chicken keeping isn&rsquot all sunshine and rainbows.

I&rsquove been around chickens my whole life and I&rsquove had my own flock for over 10 years and I&rsquove seen lots of good and a fair amount of bad.

There are literally hundreds of posts telling you why to get chickens but I thought I&rsquod let you know why you might want to think long and hard about what you&rsquore getting yourself into.

1. Are supermarket eggs fertile?

I was once contacted by a lady who had twice tried to hatch eggs using my online hatching course , without success.

When I talked to her about what was happening, it eventually transpired that she had been using eggs bought from her local supermarket.

She had understood labels saying "free range" to mean that the eggs would be fertile.

I don't blame her - as a child I tried to hatch supermarket eggs myself and was very disappointed when they weren't successful.

Any kind of egg bought in a supermarket will not be fertile.

Supermarket eggs are not fertile - not even "free range" or "organic" eggs. Commercially produced eggs are laid by hens who are either in cages, barns or pastures - but without access to a male chicken.

And without a male, a hen's eggs cannot be fertilised.

Which takes us to the next point.


Bird eggs have been valuable foodstuffs since prehistory, in both hunting societies and more recent cultures where birds were domesticated. The chicken probably was domesticated for its eggs (from jungle fowl native to tropical and subtropical Southeast Asia and Indian subcontinent) before 7500 BCE. Chickens were brought to Sumer and Egypt by 1500 BCE, and arrived in Greece around 800 BCE, where the quail had been the primary source of eggs. [5] In Thebes, Egypt, the tomb of Haremhab, dating to approximately 1420 BCE, shows a depiction of a man carrying bowls of ostrich eggs and other large eggs, presumably those of the pelican, as offerings. [6] In ancient Rome, eggs were preserved using a number of methods and meals often started with an egg course. [6] The Romans crushed the shells in their plates to prevent evil spirits from hiding there. [7] In the Middle Ages, eggs were forbidden during Lent because of their richness. [7]

Egg scrambled with acidic fruit juices were popular in France in the seventeenth century this may have been the origin of lemon curd. [8]

The dried egg industry developed in the nineteenth century, before the rise of the frozen egg industry. [9] In 1878, a company in St. Louis, Missouri started to transform egg yolk and egg white into a light-brown, meal-like substance by using a drying process. [9] The production of dried eggs significantly expanded during World War II, for use by the United States Armed Forces and its allies. [9]

In 1911, the egg carton was invented by Joseph Coyle in Smithers, British Columbia, to solve a dispute about broken eggs between a farmer in Bulkley Valley and the owner of the Aldermere Hotel. Early egg cartons were made of paper. [10]

Bird eggs are a common food and one of the most versatile ingredients used in cooking. They are important in many branches of the modern food industry. [7]

The most commonly used bird eggs are those from the chicken, duck, and goose eggs. Smaller eggs, such as quail eggs, are used occasionally as a gourmet ingredient in Western countries. Eggs are a common everyday food in many parts of Asia, such as China and Thailand, with Asian production providing 59 percent of the world total in 2013. [11]

The largest bird eggs, from ostriches, tend to be used only as special luxury food. Gull eggs are considered a delicacy in England, [12] as well as in some Scandinavian countries, particularly in Norway. In some African countries, guineafowl eggs often are seen in marketplaces, especially in the spring of each year. [13] Pheasant eggs and emu eggs are edible, but less widely available [12] sometimes they are obtainable from farmers, poulterers, or luxury grocery stores. In many countries, wild bird eggs are protected by laws which prohibit the collecting or selling of them, or permit collection only during specific periods of the year. [12]

In 2017, world production of chicken eggs was 80.1 million tonnes. The largest producers were China with 31.3 million of this total, the United States with 6.3 million, India at 4.8 million, Mexico at 2.8 million, Japan at 2.6 million, and Brazil and Russia with 2.5 million each. [14] A typical large egg factory ships a million dozen eggs per week. [15]

For the month of January 2019, the United States produced 9.41 billion eggs, with 8.2 billion for table consumption and 1.2 billion for raising chicks. [16] Americans are projected to each consume 279 eggs in 2019, the highest since 1973, but less than the 405 eggs eaten per person in 1945. [16]

During production, eggs usually are candled to check their quality. [17] The size of its air cell is determined, and the examination also reveals whether the egg was fertilized and thereby contains an embryo. [17] Depending on local regulations, eggs may be washed before being placed in egg boxes, although washing may shorten their length of freshness.

The shape of an egg resembles a prolate spheroid with one end larger than the other and has cylindrical symmetry along the long axis.

An egg is surrounded by a thin, hard shell. Thin membranes exist inside the shell. The egg yolk is suspended in the egg white by one or two spiral bands of tissue called the chalazae (from the Greek word χάλαζα, meaning 'hailstone' or 'hard lump').

Air cell

The larger end of the egg contains an air cell that forms when the contents of the egg cool down and contract after it is laid. Chicken eggs are graded according to the size of this air cell, measured during candling. A very fresh egg has a small air cell and receives a grade of AA. As the size of the air cell increases and the quality of the egg decreases, the grade moves from AA to A to B. This provides a way of testing the age of an egg: as the air cell increases in size due to air being drawn through pores in the shell as water is lost, the egg becomes less dense and the larger end of the egg will rise to increasingly shallower depths when the egg is placed in a bowl of water. A very old egg will float in the water and should not be eaten. [18]


Eggshell color is caused by pigment deposition during egg formation in the oviduct and may vary according to species and breed, from the more common white or brown to pink or speckled blue-green. Generally, chicken breeds with white ear lobes lay white eggs, whereas chickens with red ear lobes lay brown eggs. [19] Although there is no significant link between shell color and nutritional value, often there is a cultural preference for one color over another (see § Color of eggshell below). As candeling is less effective with brown eggs, they have a significantly higher incidence of blood spots. [20]


The eggshell membrane is a clear film lining the eggshell, visible when one peels a boiled egg. Primarily, it composed of fibrous proteins such as collagen type I. [21] These membranes may be used commercially as a dietary supplement.


"White" is the common name for the clear liquid (also called the albumen or the glair/glaire) contained within an egg. Colorless and transparent initially, upon cooking it turns white and opaque. In chickens, it is formed from the layers of secretions of the anterior section of the hen oviduct during the passage of the egg. [22] It forms around both fertilized and unfertilized yolks. The primary natural purpose of egg white is to protect the yolk and provide additional nutrition during the growth of the embryo.

Egg white consists primarily of approximately 90 percent water into which is dissolved 10 percent proteins (including albumins, mucoproteins, and globulins). Unlike the yolk, which is high in lipids (fats), egg white contains almost no fat and the carbohydrate content is less than one percent. Egg white has many uses in food and many other applications, including the preparation of vaccines, such as those for influenza. [23]

The yolk in a newly laid egg is round and firm. As the yolk ages, it absorbs water from the albumen, which increases its size and causes it to stretch and weaken the vitelline membrane (the clear casing enclosing the yolk). The resulting effect is a flattened and enlarged yolk shape.

Yolk color is dependent on the diet of the hen. If the diet contains yellow or orange plant pigments known as xanthophylls, then they are deposited in the yolk, coloring it. Lutein is the most abundant pigment in egg yolk. [24] A diet without such colorful foods may result in an almost colorless yolk. Yolk color is, for example, enhanced if the diet includes foods such as yellow corn and marigold petals. [25] In the US, the use of artificial color additives is forbidden. [25]


Abnormalities that have been found in eggs purchased for human consumption include:

  • Double-yolk eggs, when an egg contains two or more yolks, occurs when ovulation occurs too rapidly, or when one yolk becomes joined with another yolk. [26]
  • Yolkless eggs, which contain whites but no yolk, usually occurs during a pullet's first effort, produced before her laying mechanism is fully ready. [27]
  • Double-shelled eggs, where an egg may have two or more outer shells, is caused by a counter-peristalsis contraction and occurs when a second oocyte is released by the ovary before the first egg has completely traveled through the oviduct and been laid. [28]
  • Shell-less or thin-shelled eggs may be caused by egg drop syndrome. [29]

Types of dishes

Chicken eggs are widely used in many types of dishes, both sweet and savory, including many baked goods. Some of the most common preparation methods include scrambled, fried, poached, hard-boiled, soft-boiled, omelettes, and pickled. They also may be eaten raw, although this is not recommended for people who may be especially susceptible to salmonellosis, such as the elderly, the infirm, or pregnant women. In addition, the protein in raw eggs is only 51 percent bioavailable, whereas that of a cooked egg is nearer 91 percent bioavailable, meaning the protein of cooked eggs is nearly twice as absorbable as the protein from raw eggs. [30]

As a cooking ingredient, egg yolks are an important emulsifier in the kitchen, and are also used as a thickener, as in custards.

The albumen (egg white) contains protein, but little or no fat, and may be used in cooking separately from the yolk. The proteins in egg white allow it to form foams and aerated dishes. Egg whites may be aerated or whipped to a light, fluffy consistency, and often are used in desserts such as meringues and mousse.

Ground eggshells sometimes are used as a food additive to deliver calcium. [31] Every part of an egg is edible, [ citation needed ] although the eggshell is generally discarded. Some recipes call for immature or unlaid eggs, which are harvested after the hen is slaughtered or cooked, while still inside the chicken. [32]


Eggs contain multiple proteins that gel at different temperatures within the yolk and the white, and the temperature determines the gelling time. Egg yolk becomes a gel, or solidifies, between 65 and 70 °C (149 and 158 °F). Egg white gels at different temperatures: 60 to 73 °C (140 to 163 °F). The white contains exterior albumen which sets at the highest temperature. [33] In practice, in many cooking processes the white gels first because it is exposed to higher temperatures for longer. [34] [35]

Salmonella is killed instantly at 71 °C (160 °F), but also is killed from 54.5 °C (130.1 °F), if held at that temperature for sufficiently long time periods. [34] To avoid the issue of salmonella, eggs may be pasteurized in-shell at 57 °C (135 °F) for an hour and 15 minutes. Although the white then is slightly milkier, the eggs may be used in normal ways. Whipping for meringue takes significantly longer, but the final volume is virtually the same. [36]

If a boiled egg is overcooked, a greenish ring sometimes appears around egg yolk due to changes to the iron and sulfur compounds in the egg. It also may occur with an abundance of iron in the cooking water. [ citation needed ] Overcooking harms the quality of the protein. [37] Chilling an overcooked egg for a few minutes in cold water until it is completely cooled may prevent the greenish ring from forming on the surface of the yolk.

Peeling a cooked egg is easiest when the egg was put into boiling water as opposed to slowly heating the egg from a start in cold water. [38]

Flavor variations

Although the age of the egg and the conditions of its storage have a greater influence, the bird's diet affects the flavor of the egg. [8] For example, when a brown-egg chicken breed eats rapeseed (canola) or soy meals, its intestinal microbes metabolize them into fishy-smelling triethylamine, which ends up in the egg. [8] The unpredictable diet of free-range hens will produce likewise, unpredictable egg flavors. [8] Duck eggs tend to have a flavor distinct from, but still resembling, chicken eggs.

Eggs may be soaked in mixtures to absorb flavor. Tea eggs, a common snack sold from street-side carts in China, are steeped in a brew from a mixture of various spices, soy sauce, and black tea leaves to give flavor.


Careful storage of edible eggs is extremely important, as an improperly handled egg may contain elevated levels of Salmonella bacteria that may cause severe food poisoning. In the US, eggs are washed. This cleans the shell, but erodes its cuticle. [39] [40] The USDA thus recommends refrigerating eggs to prevent the growth of Salmonella. [25]

Refrigeration also preserves the taste and texture, however, intact eggs (unwashed and unbroken) may be left unrefrigerated for several months without spoiling. [41] In Europe, eggs are not usually washed, and the shells are dirtier, however the cuticle is undamaged, and they do not require refrigeration. [40] In the UK in particular, hens are immunized against salmonella and generally, their eggs are safe for 21 days. [40]


The simplest method to preserve an egg is to treat it with salt. Salt draws water out of bacteria and molds, which prevents their growth. [42] The Chinese salted duck egg is made by immersing duck eggs in brine, or coating them individually with a paste of salt and mud or clay. The eggs stop absorbing salt after approximately a month, having reached osmotic equilibrium. [42] Their yolks take on an orange-red color and solidify, but the white remains somewhat liquid. These often are boiled before consumption and are served with rice congee.

Another method is to make pickled eggs, by boiling them first and immersing them in a mixture of vinegar, salt, and spices, such as ginger or allspice. Frequently, beetroot juice is added to impart a red color to the eggs. [43] If the eggs are immersed in it for a few hours, the distinct red, white, and yellow colors may be seen when the eggs are sliced. [43] If marinated for several days or more, the red color will reach the yolk. [43] If the eggs are marinated in the mixture for several weeks or more, the vinegar will dissolve much of the shell's calcium carbonate and penetrate the egg, making it acidic enough to inhibit the growth of bacteria and molds. [42] Pickled eggs made this way generally keep for a year or more without refrigeration. [42]

A century egg or hundred-year-old egg is preserved by coating an egg in a mixture of clay, wood ash, salt, lime, and rice straw for several weeks to several months, depending on the method of processing. After the process is completed, the yolk becomes a dark green, cream-like substance with a strong odor of sulfur and ammonia, while the white becomes a dark brown, transparent jelly with a comparatively mild, distinct flavor. The transforming agent in a century egg is its alkaline material, which gradually raises the pH of the egg from approximately 9 to 12 or more. [44] This chemical process breaks down some of the complex, flavorless proteins and fats of the yolk into simpler, flavorful ones, which in some way may be thought of as an "inorganic" version of fermentation.

Cooking substitutes

For those who do not consume eggs, alternatives used in baking include other rising agents or binding materials, such as ground flax seeds or potato starch flour. Tofu also acts as a partial binding agent, since it is high in lecithin due to its soy content. Applesauce may be used, as well as arrowroot and banana. Extracted soybean lecithin, in turn, often is used in packaged foods as an inexpensive substitute for egg-derived lecithin. Leguminous broths, such as chickpea brine or green pea canning liquid, also known as aquafaba, can replace egg whites in desserts such as meringues and mousses.

Other egg substitutes are made from just the white of the egg for those who worry about the high cholesterol and fat content in eggs. These products usually have added vitamins and minerals, as well as vegetable-based emulsifiers and thickeners, such as xanthan gum or guar gum. These allow the product to maintain the nutrition and several culinary properties of real eggs, making possible foods such as Hollandaise sauce, custard, mayonnaise, and most baked goods with these substitutes.

Egg sizes

Nutritional value

A 50-gram (1.8 oz) medium/large chicken egg provides approximately 70 kilocalories (290 kJ) of food energy and 6 grams of protein. [45] [46]

Eggs (boiled) supply several vitamins and minerals as significant amounts of the Daily Value (DV), including vitamin A (19 percent DV), riboflavin (42 percent DV), pantothenic acid (28 percent DV), vitamin B12 (46 percent DV), choline (60 percent DV), phosphorus (25 percent DV), zinc (11 percent DV) and vitamin D (15 percent DV). Cooking methods affect the nutritional values of eggs.

The diet of laying hens also may affect the nutritional quality of eggs. For instance, chicken eggs that are especially high in omega-3 fatty acids are produced by feeding hens a diet containing polyunsaturated fats from sources such as fish oil, chia seeds, or flaxseeds. [47] Pasture-raised free-range hens, which forage for their own food, also produce eggs that are relatively enriched in omega-3 fatty acids when compared to those of cage-raised chickens. [48] [49]

A 2010 USDA study determined there were no significant differences of macronutrients in various chicken eggs. [50]

Cooked eggs are easier to digest than raw eggs, [51] as well as having a lower risk of salmonellosis. [52]

Cholesterol and fat

More than half the calories found in eggs come from the fat in the yolk 50 grams of chicken egg (the contents of an egg just large enough to be classified as "large" in the US, but "medium" in Europe) contains approximately five grams of fat. Saturated fat (palmitic, stearic, and myristic acids) makes up 27 percent of the fat in egg. [53] The egg white consists primarily of water (around 90 percent) and protein (around 10 percent) and contains no cholesterol and little, if any, fat. [54]

There is debate over whether egg yolk presents a health risk. Some research suggests dietary cholesterol increases the ratio of total to HDL cholesterol and, therefore, adversely affects the body's cholesterol profile [55] whereas other studies show that moderate consumption of eggs, up to one a day, does not appear to increase heart disease risk in healthy individuals. [56] Harold McGee argues that the cholesterol in the egg yolk is not what causes a problem, because fat (particularly saturated fat) is much more likely to raise cholesterol levels than the consumption of cholesterol. [18]

Type 2 diabetes

Studies have shown conflicting results about a possible connection between egg consumption and type 2 diabetes. A 1999 prospective study of more than 117,000 people by the Harvard School of Public Health concluded in part, that "The apparent increased risk of CHD associated with higher egg consumption among diabetic participants warrants further research." [57] A 2008 study by the Physicians' Health Study I (1982–2007) and the Women's Health Study (1992–2007) determined the "data suggest that high levels of egg consumption (daily) are associated with an increased risk of type 2 diabetes", [58] however, a study published in 2010 found no link between egg consumption and type 2 diabetes. [59] A meta-analysis from 2013 found that eating four eggs per week was associated with a 29 percent increase in the relative risk of developing diabetes. [60] Another meta-analysis from 2013 also supported the idea that egg consumption may lead to an increased incidence of type two diabetes. [61] A 2020 meta-analysis found that there was no overall association between moderate egg consumption and risk of type 2 diabetes and that the risk found in US studies was not found in European or Asian studies. [62]

Cardiovascular risk

Eggs are one of the largest sources of phosphatidylcholine (lecithin) in the human diet. [63] A study published in the scientific journal, Nature, showed that dietary phosphatidylcholine is digested by bacteria in the gut and eventually converted into the compound TMAO, a compound linked with increased heart disease. [64] [65] Another study found that type 2 diabetes mellitus and kidney disease also increase TMAO levels and that evidence for a link between TMAO and cardiovascular diseases may be due to confounding or reverse causality. [66]

A 1999 Harvard School of Public Health study of 37,851 men and 80,082 women concluded that its "findings suggest that consumption of up to 1 egg per day is unlikely to have substantial overall impact on the risk of CHD or stroke among healthy men and women." [57] In a study of 4,000 people, scientists found that eating eggs increased blood levels of a metabolite promoting atherosclerosis, TMAO, and that this in turn caused significantly higher risk of heart attack and stroke after three years of follow-up. [67]

A 2007 study of nearly 10,000 adults demonstrated no correlation between moderate (six per week) egg consumption and cardiovascular disease or strokes, except in the subpopulation of diabetic patients who also presented an increased risk of coronary artery disease. [68] One potential alternative explanation for the null finding is that background dietary cholesterol may be so high in the usual Western diet that adding somewhat more has little further effect on blood cholesterol. [69] Other research supports the idea that a high egg intake increases cardiovascular risk in diabetic patients. [70] A 2009 prospective cohort study of more than 21,000 individuals suggests that "egg consumption up to 6 [per] week has no major effect on the risk of cardiovascular disease and mortality and that consumption of [more than 7 a week] is associated with a modest increased risk of total mortality" in males, whereas among males with diabetes, "any egg consumption is associated with an increased risk of all-cause mortality and there was suggestive evidence for an increased risk of myocardial infarction and stroke". [71]

A 2013 meta-analysis found no association between egg consumption and heart disease or stroke. [72] [73] A 2013 systematic review and meta-analysis found no association between egg consumption and cardiovascular disease or cardiovascular disease mortality, but did find egg consumption of more than once daily increased cardiovascular disease risk 1.69-fold in those with type 2 diabetes mellitus when compared to type 2 diabetics who ate less than one egg per week. [61] Another 2013 meta-analysis found that eating four eggs per week increased the risk of cardiovascular disease by six percent. [60]

In 2020, two meta-analyses found that moderate egg consumption (up to one egg a day) is not associated with an increased cardiovascular disease risk. [74] [75] A 2020 umbrella review concluded that increased egg consumption is not associated with cardiovascular disease risk in the general population. [76]


A health issue associated with eggs is contamination by pathogenic bacteria, such as Salmonella enteritidis. Contamination of eggs with other members of the genus Salmonella while exiting a female bird via the cloaca may occur, so care must be taken to prevent the egg shell from becoming contaminated with fecal matter. In commercial practice in the US, eggs are quickly washed with a sanitizing solution within minutes of being laid. The risk of infection from raw or undercooked eggs is dependent in part upon the sanitary conditions under which the hens are kept.

Health experts advise people to refrigerate washed eggs, use them within two weeks, cook them thoroughly, and never consume raw eggs. [52] As with meat, containers and surfaces that have been used to process raw eggs should not come in contact with ready-to-eat food.

A study by the U.S. Department of Agriculture in 2002 (Risk Analysis April 2002 22(2):203-18) suggests the problem is not so prevalent in the U.S. as once thought. It showed that of the 69 billion eggs produced annually, only 2.3 million are contaminated with Salmonella—equivalent to just one in every 30,000 eggs—thus showing Salmonella infection is quite rarely induced by eggs. This has not been the case in other countries, however, where Salmonella enteritidis and Salmonella typhimurium infections due to egg consumption are major concerns. [77] [78] [79] Egg shells act as hermetic seals that guard against bacteria entering, but this seal can be broken through improper handling or if laid by unhealthy chickens. Most forms of contamination enter through such weaknesses in the shell. In the UK, the British Egg Industry Council awards the lions stamp to eggs that, among other things, come from hens that have been vaccinated against Salmonella. [80] [81] [82]

In 2017, authorities blocked millions of eggs from sale in the Netherlands, Belgium, and Germany because of contamination with the insecticide fipronil. [83]

Food allergy

One of the most common food allergies in infants is eggs. [84] Infants usually have the opportunity to grow out of this allergy during childhood, if exposure is minimized. [85] Allergic reactions against egg white are more common than reactions against egg yolks. [86] In addition to true allergic reactions, some people experience a food intolerance to egg whites. [86] Food labeling practices in most developed countries now include eggs, egg products, and the processing of foods on equipment that also process foods containing eggs in a special allergen alert section of the ingredients on the labels. [87]

Connecting the Dots: Chickens, Primates and Humans

An article in Science Daily called Bird brain? Birds and humans have similar brain wiring (July, 2013) presents the findings of a research team at the Imperial College London who found that “areas [of the brains of humans and birds] important for high-level cognition, such as long-term memory and problem solving, are wired up to other regions of the brain in a similar way.” Professor Murray Shanahan, author of the study, wrote: “Birds have been evolving separately from mammals for around 300 million years, so it is hardly surprising that under a microscope the brain of a bird looks quite different from a mammal. Yet, birds have been shown to be remarkably intelligent in a similar way to mammals such as humans and monkeys.”

Lesley Rogers, Emeritus Professor of Neuroscience at University of New England, has made outstanding contributions to understanding brain development and behavior. She discovered lateralization in the chick forebrain, when lateralization was still believed to be a unique feature of the human brain. Later it became known that hemispheric specialization is ubiquitous in the animal kingdom.

Yet, as many animal ethicists and behavioral experts point out, there are problems with these comparisons that prevent us from a more authentic understanding of how chickens think and feel. Karen Davis, Ph.D., president of United Poultry Concerns, has presented a tremendously thought-provoking analysis of cross-species comparisons in her article entitled, Are Chickens Smarter Than Toddlers? A View of Cross-Species Comparisons. Leading avian neurologist and researcher Lesley Rogers argues that instead of ranking animals according to a simplistic, anthropocentric model of intelligence, we would be more accurate and just in our assessments if we recognized that there are many different measures and kinds of intelligence. And evolutionary biologist Marc Bekoff explains in his article, Are Pigs as Smart as Dogs and Does it Really Matter?, that such comparisons are silly and dangerous, as if to suggest dumber animals suffer less than smarter ones.

Moreover, we’ll never be able to know for certain what forms of intelligence other animals might possess that could simply be outside of human understanding. As author Annie Potts explains, “While chickens display feelings comparable to those of humans (such as grief, fear or happiness), they no doubt also possess their own exceptional forms of emotion and consciousness that even the most rigorous scientific tests may not begin to uncover — simply because these inimitable perspectives of chickens do not register conceptually or experientially within the human domain.” (4)

photo: Willowite Animal Sanctuary

In A Coop

While a coop is not necessary for chickens to breed, all of the chickens' breeding patterns can be facilitated by having them within the confines of one. The small size of the coop also ensures chickens cannot wander too far from one another, so are significantly more likely to breed.

When Are Eggs Fertile?

An egg will only yield a chick if the hen has mated with a rooster before the egg was formed. Most production-oriented farms don't have a rooster milling about, unless it's time to make a new batch of egg-laying hens. This means that almost all eggs in the supermarket are unfertilized.

Roosters are more often seen in small or hobby flocks. With farm-fresh eggs obtained from a smaller flock, it is likely that almost every egg is potentially fertile. But don't worry: the embryo is usually a mere speck on the yolk, and stops growing when the egg is refrigerated. Fertilized eggs require twenty-one days of incubation at a specific temperature (the temperature it would be under a mother chicken) in order to produce chicks.

In outdoor conditions, chickens will breed when the days begin to get long in spring. While the rooster will mate with his hens throughout the year, she typically only incubates eggs when conditions are optimal. A hen choosing to incubate eggs is said to have "gone broody."

As a chicken farmer, it’s vital that you learn more about the average chicken life cycle. What goes on between the egg stage until the end of the chicken’s lifespan? Or is it the chicken that came before the egg :)? How long do chickens live? How much do you know about the developmental stages that chickens go through? In this article, we’ll be exploring a chicken’s life stages and important information that backyard farmers need to have knowledge of, at each stage.

Chicken Life Span

Chickens aren’t just for farming anymore. A lot of people have chickens as pets/companions and would prefer that their chickens live for a long time.

Most breeds of chickens would live a minimum of three years and a maximum of five years. Breeds such as Plymouth Rock, Easter Eggers, Orpingtons and Old English Game Foul often live as long as seven plus years. A chicken known as Matilda lived for up to 16 years and was in the Guinness World Records as the world’s most long-lived chicken.

To ensure that chickens do not die prematurely, farmers should provide for the chicken’s needs based on the chicken’s stage of life. If you want to maximize the life span of your chickens, then you have to consider the factors that affect the chicken’s life span.

The Chicken Life Cycle Diagram

These include nutrition, pests and diseases, environment, housing, genetics, and veterinary care. Poultry farmers or keepers should take into consideration how they manage their flock with respect to the above factors.

Phases of a chicken’s life cycle

The life cycle of a chicken is in four sequential stages: egg, chick, pullet, and hen.

Egg Stage

In this stage, a hen lays an egg which is the start of the life of the new chicken. Although laying hens produce eggs every 25-27 hours, the eggs cannot hatch into chicks unless the hen was fertilized by a rooster.

The process from the creation of the egg to its being laid takes about 25 hours. The biology of the egg formation process begins with the formation of yolk (also called oocyte), which is produced during ovulation. It is fertilized by the rooster’s sperm and travels down the oviduct where it is gradually covered by the vitelline membrane, the albumen, and the external shell.

Choose the Incubation Method that Best Suits You

Fertile eggs can be incubated by the hen herself or by an artificial incubator. A lot of backyard farmers prefer a natural, organic way of creating new chicks and would allow natural incubation by the hen. In this case, the hen would lay sufficient eggs of about ten to twelve in her nest and then commence the brooding process.

Typically, brooding in hens entails sitting on the eggs for 21 days or more till the chicks hatch. During this period, the hen is temperamental. Just before hatching, the chicks absorb all the nutrients from the egg into their body. These nutrients are needed for sustenance by the chicks for the first 1-3 days.

If you choose the incubation option, the chicks will need immediate and proper care as soon as they are hatched. Whereas, in natural incubation (a favorite of backyard farmers), the hen would be responsible in the early days for the raising of the chicks.

It is crucial that hens are well taken care of to avoid problems with the eggs. The broody hens should be provided with food and water, and laying eggs should get enough calcium in their meal.

Chick Stage

After the chicks are hatched, they would require feed and water as well as warmth. Starter chick feed, rich in protein, is required for artificially incubated chicks. Lighting is also needed for warmth. Incubated chicks need to get constant water and would also have to be directed to feed from their feed bowls.

Close observation is necessary to ensure that those chicks that are not eating are provided feed. Temperature control is essential: the temperature should be warm after hatching and gradually reduced to room temperature towards the 4 th -5 th week.

Points to Note About Natural Brooding

Some farmers use a brooder for the entire chick stage. The brooder is an indoor space that is heated up using an infrared lamp. It must be climate controlled with proper ventilation. It would also contain absorbent bedding (no newspaper, recommended bedding is thin pine shavings) and drinkers/feeders.

In the case of chicks raised by their mother, they would be under the hen’s wings initially, and that would provide warmth for them. In this case, you should provide separate quarters for the hen and her chicks.

The feed should be placed in the hen’s nest, and the hen would usually do a good job of making each chick eat and drink. After 3-4 weeks, you can start providing separate feed for the chicks.

Poultry health is most critical at the chick stage. You may need to consult with a veterinarian to establish a vaccination schedule and protect the chicks against any future diseases.

Whether to Vaccinate or Not

However, many backyard farmers choose not to vaccinate their birds. There are many benefits to not vaccinating the chicks, especially if you are not running a commercial poultry. In this case, you should ensure that hygiene and adequate nutrition standards are met in your management of the new chickens. In their first meals, you should provide electrolytes and extra nutrients.

The chick stage should last for 4-5 weeks, and then, the chicks would no longer require starter feed. During this time, they’d sprout more prominent feathers and depending on your farming goals, require different feed types.

Take Steps to Avoid Pecking

You will also need to watch out so the chicks don’t injure each other from pecking as there is often a “battle” for the pecking order towards the end of the chick stage. For the first 4-5 weeks, chicks require constant care and monitoring. Backyard farmers should make out enough time to avoid mortality as the mortality rate of chickens is very high at this stage.

Pullet Stage

After 5 weeks until they are about 20 weeks, the chicks are now pullets. Pullets are like the human version of adolescents. They are not as fragile as chicks, but at the same time, they do not have the hardiness of hens or adult roosters.

If you used a brooder during the chick stage, you can now take the chicks out of the brooder and mix them up with the older birds. However, you should be on the watch for bullying. This can cause the pullets injuries (as they are younger and weaker) and feather loss. Some farmers after doing a lot of work in the chick stage neglect their birds once they reach the pullet stage. Don’t be that farmer! Alternatively, you may house the pullets in isolation from older birds.

What if I Run a Free Range Farm?

Even if you are running a free-range farm, you should still devote some time to caring for the pullets. From 5-8 weeks, gradually reduce the amount of starter and replace with regular chick meal. Feed and water should be provided twice daily.

At eight weeks, you should start feeding them grower’s mash to spur the growth required for laying. Pullets usually start laying their first eggs at 18-20 weeks. The initial eggs would be small, as the birds are still pullets. To improve their egg production, you would need to start feeding them layer’s mash.

What to Do Before Moving Pullets

Pullets are often moved to individual laying cages (for layer hens). In this case, the movement may cause stress to the pullet. Before moving pullets to the laying coop, we recommend that you do so in three to four days, and be sure to include electrolytes and water-soluble vitamins in the drinking water. This should also be done in the first three to four days after transferring them. Birds should be handled gently during movement to prevent injuries.

Hen Stage

At 18 weeks and above, the pullets become hens. Even though hens are lower maintenance than pullets and chicks, you still need to dedicate up to an hour a day to managing the chickens.

This is the stage where the life of a chicken becomes a cycle. Those chicks that were hatched and looking like they would die at any moment are now ready to lay eggs which would restart the cycle. If you are raising chickens for their eggs, then from the 18 th week, you should start feeding the hens a specially formulated layer’s mash. If you had cockerels in your flock since the chick stage, this is the time to relocate them to another pen.

Some Management Issues with Hens You Should be Aware Of

Hens come with special management issues. One of these is molting. Molting usually begins at the end of the main egg-laying season. Since protein is required to make new feathers, you will notice that there is a reduction in the number of eggs laid as the chickens shed their feathers. Special nutrition has to be provided during the molting period. Another issue to sort out as a poultry farmer is in-fighting between the chickens as they try to establish a pecking order. It is essential that you be observant to prevent chickens from cannibalizing each other.

The egg production of the hens would usually be steady for the first year but then would start to drop after about 70-75 weeks. They would still lay, but then the egg production would not be daily. As the hens get older, they become arthritic and less energetic, with poor egg production. Some hens could continue to lay intermittently for up to 7 years. However the cost of continuing to feed old layers would still remain and to defray these costs, some farmers choose to cull old layers and sell them off for meat.

Rooster Life Cycle

Most of the information above deals with hens, as most backyard farmers often prefer hens due to their egg laying. However, a flock usually contains chicks, pullets, hens, and roosters. What is the life cycle of a rooster? It is not different from that of the layers. Roosters, just like hens, start out as eggs which hatch into chicks.

After 5 weeks, they grow into cockerels and begin to develop the plumage that characterizes cocks. They don’t have any special nutritional requirements, and so long as adequate nutrients are provided, they eventually grow into roosters.

At 16-18 weeks, they begin to crow. To improve the taste of the meat, some roosters get castrated through the process of caponization. Others are kept for breeding purpose and are used to continue the life cycle of a new chicken. This is so because roosters are needed to fertilize the hens to produce eggs that can develop into chicks.

The YouTube video below illustrates as a presentation, the life cycle of a chicken.

In summary

  • All Chickens or Roosters start as eggs.
  • These eggs hatch into chicks, either naturally (through brooding) or in an incubator
  • The chicks grow to become pullets or cockerels
  • Finally, they become hens or roosters.

Farmers must provide adequate care to their chickens, depending on the stage of their life cycle. This would help maximize value from the entire flock. Many farmers complain of high chick mortality. This is often because they do not understand that newly hatched chicks are very frail. Some farmers also complain of poor egg production or inadequate meat yield. This may be due to poor nutrition. By understanding the life cycle of chickens, farmers can tailor nutrition and other care to the chicken’s needs and avoid problems like mortality or inadequate yield.

What Is Coccidiosis? Signs And Treatment In Chickens

Coccidia you’ve likely heard of it if you own any type of farm animal. Let’s take a look at what exactly is coccidia, how to diagnose an infection in your poultry, and how to best deal with an infection.

It is true that coccidia can infect a wide range of animals, especially cattle, pigs, goats, sheep, rabbits and chickens. But typically each species of animal has its own specific “type” of coccidia that infects it and cross-species infections are not common. For example, there are about 5 specific types of Eimeria coccidia that infect rabbits, but none of those types are able to infect chickens to any severity because poultry have their own “type” of Eimeria coccidia that infect them. Think of it like our house keys. They all look similar, but my house key doesn’t open your front door and vice versa.

What Is Coccidia?

Coccidia is the common term used to describe a group of parasites called protozoa. If you can recall your high school biology class, protozoa are classified as single-celled animals similar to amoeba or single-celled plants that we know as algae. Coccidia are bigger than bacteria, but still microscopic. Coccidia can be found everywhere in the world on both land and water.

The oocyst is the form of coccidia that lives in the environment. For poultry, the biggest source of coccidia oocysts can be found in the coop litter and run area. Since coccidia can be found naturally in the environment, chickens can become infected when they forage in the yard. A chicken ingests the oocyst, passes into the chicken’s digestive tract where the oocyst then transforms into a second developmental stage and seeks out the intestinal lining of the chicken host. In the warm, moist environment of the chicken’s intestines, the coccidia rapidly develops into its replicating phase and explodes in population, causing damage to the intestinal lining of the chicken. At this point, the chicken may begin to show some clinical signs as the coccidia infection advances. Acute symptoms such as bloody diarrhea, listlessness and poor weight gain may be evident.


Now that you have a basic understanding of what coccidia is and what it looks like in poultry, how do we treat an active infection? It’s important to immediately do a complete cleanout of all coop floor litter and nest box material. Getting as much of the infected manure out and away from your chickens is the first step in slowing the spread of oocysts. Remove the bedding to a compost bin or burn pile. As long as you hot compost the manure and bedding and then allow it to set for a year, it should be safe to use in your garden. Also scrub and disinfect all waterers and refill with fresh water. At the same time, I prefer to add a coccidiostat such as liquid Corid to the drinking water. Use a rate of 1 teaspoon per gallon of water for the first 5 days, then I switch to a lower dose of ½ teaspoon per gallon for another 2 weeks or so. By this time, the birds have been protected long enough to have developed their own immunity to the coccidia species that they are facing.

Coccidia is perhaps the most common infective agent likely to cause illness in your chicks or adult chickens. It’s not a matter of if you will deal with it, but when. Our goal is to help you be ready to deal with it when coccidia does show up in your brooder or coop. Leave us a comment below and let us know about your experience in dealing with coccidia in chickens.

Hofstadter’s Spherical Chickens

I really love the comedic series “The Big Bang Theory”, however in the episode “The Cooper-Hofstadter Polarization”, Leonard recites a joke that greatly amuses Howard, Raj and even Sheldon. At this point during the episode, I felt my own countenance mirror Penny’s as I was left deeply confused.

“There’s this farmer, and he has these chickens, but they won’t lay any eggs. So, he calls a physicist to help. The physicist then does some calculations, and he says, um, I have a solution, but it only works with spherical chickens in a vacuum.”

The origins of this joke come from the notion of a spherical cow. In theoretical physics, problems are complex and difficult to imagine, and so a spherical cow in a vacuum is used to simplify the problem, even though this simplification may lead to inaccuracies when applying the solution- once found!- to real life. For example, when creating models of motions, certain conditions must be taken into account
• Air resistance
• Air density and any variations of this
• If the gravitational field is constant, or if gravitational interactions happen due to large objects nearby
• If the object is flexible, inflexible or semi-rigid
• If there are any electromagnetic or electrostatic interactions

Therefore, physicists use the spherical cow in a vacuum. The vacuum means that many of the conditions, such as air resistance, do not have to be considered. This is because there are no particles, including air particles, in vacuums.

The cow is spherical, as spheres have minimal surface areas. This keeps heat transfer- through radiation- minimal. A good biology comparison for this is to consider the small intestine. Molecules of broken down food pass through the small intestine, where absorption takes place this means the important nutrients in the food- such as glucose- will pass through the walls of the intestine and into the bloodstream where they will be assimilated. The larger the surface area, the more opportunity for absorption. Therefore, the small intestine is lined with villi and microvilli, to increase the surface area and create more opportunity for absorption. On the other hand, physicists want minimal heat loss when calculating theories. The cow is therefore spherical, as there is as little opportunity for heat loss as possible because the surface area to volume ratio is low.

Villi mean that the small intestine has a larger surface area, photo from

Therefore, Leonard’s joke implies that he has calculated a theory for the farmer’s chickens not laying eggs, however because he has simplified the problem to make it possible, the solution only works with spherical chickens in a vacuum. Bazinga!

Balut egg can be seen on reality TV Show.

The TELEVISION Show Survivor that pits rivals versus each other to consider one the program&rsquos sole survivor has had its share of extreme challenges since its inception. Since its start, challengers were required to consume pig brains, tarantulas, scorpions, and, you guessed it&ndash Balut.

While some Survivor fans would enjoy taking on the delicacy challenge, one fan saying Balut is &ldquoone of Cambodian favorites snack. It tastes yummy,&rdquo the show&rsquos host, Jeff Probst, does not share the same enjoyment.

When asked what he would consider the most horrible challenge dish of all time, Balut was the answer without pause. &ldquoThose little heads, that tiny body, those light feathers,&rdquo he says. &ldquo

And the craziest part of all, those are offered in Asian grocery stores in the same manner we sell potato chips.&rdquo Probst makes a much better host than a competitor as some survivors could finish the challenge. A little accomplishment for what might win you a $1 million reward.

Watch the video: Αυτά είναι τα καλά αυγά. Τα υπόλοιπα δεν πρέπει να τα φάτε ειδικά αν έχετε μικρό παιδί. (February 2023).