Chicken

Chicken
A Rhode Island Red
Conservation status
Template:StatusDomesticated
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Galliformes
Family:	Phasianidae
Genus:	Gallus
Species:	G. gallus

A chicken (Gallus gallus) is a type of domesticated bird which is often raised as a type of poultry. It is believed to be descended from the wild Indian and south-east Asian Red Junglefowl.

With a population of more than 24 billion in 2003, there are more chickens in the world than any other bird. They provide two sources of food frequently consumed by humans: their meat, and their eggs.

General biology and habitat

Chicken eggs vary in color depending on the hen, typically ranging from bright white to shades of brown and even blue, green, and recently reported purple (found in South Asia) (Araucana varieties).

Rooster crowing during daylight hours

Male chickens are known as roosters (in the U.S., Canada and Australia), cocks, or cockerels. Castrated roosters are called capons. Female chickens are known as hens, or 'chooks' in Australian English. Young females are known as pullets. Roosters can usually be differentiated from hens by their striking plumage, marked by long flowing tails and bright pointed feathers on their necks.

However, in some breeds, such as the Sebright, the cock only has slightly pointed neck feathers, and the identification must be made by looking at the comb. Chickens have a fleshy crest on their heads called a comb or cockscomb, and a fleshy piece of hanging skin under their beak called a wattle. These organs help to cool the bird by redirecting blood flow to the skin. Both the male and female have distinctive wattles and combs. In males, the combs are often more prominent, though this is not the case in all varieties.

Domestic chickens are typically fed commercially prepared feed that includes a protein source as well as grains. Chickens often scratch at the soil to get at adult insects and larvae or seed. Incidents of cannibalism can occur when a curious bird pecks at a preexisting wound or during fighting (even among female birds). This is exacerbated in close quarters. In commercial egg and meat production this is controlled by trimming the beak (removal of ⅔ of the top half and occasionally ⅓ of the lower half of the beak).

Domestic chickens are not capable of long distance flight, although they are generally capable of flying for short distances such as over fences. Chickens will sometimes fly to explore their surroundings, but usually only to flee perceived danger. Because of flight risk, chickens raised in open-air pens generally have one of their wings clipped by the breeder — the tips of the longest feathers on one of the wings are cut, resulting in unbalanced flight which the bird cannot sustain for more than a few meters (more on wing clipping).

Chickens are gregarious birds and live together as a flock. They have a communal approach to the incubation of eggs and raising of young. Individual chickens in a flock will dominate others, establishing a "pecking order," with dominant individuals having priority for access to food and nesting locations. Removing hens or roosters from a flock causes a temporary disruption to this social order until a new pecking order is established.

Chickens will try to lay in nests that already contain eggs, and have been known to move eggs from neighbouring nests into their own. Some farmers use fake eggs made from plastic or stone to encourage hens to lay in a particular location. The result of this behavior is that a flock will use only a few preferred locations, rather than having a different nest for every bird.

Hens can also be extremely stubborn about always laying in the same location. It is not unknown for two (or more) hens to try to share the same nest at the same time. If the nest is small, or one of the hens is particularly determined, this may result in chickens trying to lay on top of each other.

Contrary to popular belief, roosters do not crow only at dawn, but may crow at any time of the day or night. Their crowing - a loud and sometimes shrill call - is a territorial signal to other roosters. However, crowing may also result from sudden disturbances within their surroundings.

Recent studies [1] have shown that chickens (and possibly other bird species) still retain the genetic blueprints to produce teeth in the jaws, although these are dormant in living animals. These are a holdover from primitive birds such as Archaeopteryx, which were descended from theropod dinosaurs. (It has been suggested that chickens are related to Tyrannosaurus rex. [2])

Courting

A free roaming chicken family of rooster, hen and six chicks as seen on the streets of downtown Key West, Florida

When a rooster finds food he may call the other chickens to eat it first. He does this by clucking in a high pitch as well as picking up and dropping the food. This behavior can also be observed in mother hens, calling their chicks. In some cases the rooster will drag the wing opposite the hen on the ground, while circling her. This is part of chicken courting ritual. When a hen is used to coming to his "call" the rooster may mount the hen and proceed with the fertilization.

Going broody

A broody Rhode Island Red hen guarding her eggs

Sometimes a hen will stop laying and instead will focus on the incubation of eggs, a state that is commonly known as going broody. A broody chicken will sit fast on the nest, and protest or peck in defense if disturbed or removed, and will rarely leave the nest to eat, drink, or dust bathe. While brooding, the hen maintains constant temperature and humidity, as well as turning the eggs regularly.

At the end of the incubation period, which is an average of 21 days, the eggs (if fertilized) will hatch, and the broody hen will take care of her young. Since individual eggs do not all hatch at exactly the same time (the chicken can only lay one egg approximately every 25 hours), the hen will usually stay on the nest for about two days after the first egg hatches. During this time, the newly-hatched chicks live off the egg yolk they absorb just before hatching. The hen can sense the chicks peeping inside the eggs, and will gently cluck to stimulate them to break out of their shells. If the eggs are not fertilized by a rooster and do not hatch, the hen will eventually lose interest and leave the nest.

Modern egg-laying breeds rarely go broody, and those that do often stop part-way through the incubation cycle. Some breeds, such as the Cochin, Cornish and Silkie, regularly go broody and make excellent maternal figures. Chickens used in this capacity are known as utility chickens.

Artificial incubation

Chicken egg incubation can successfully occur artificially as well. Nearly all chicken eggs will hatch after 21 days of good conditions - 99.5 °F (37.5°C) and around 55% relative humidity (increase to 70% in the last three days of incubation to help soften egg shell). Many commercial incubators are industrial-sized with shelves holding tens of thousands of eggs at a time, with rotation of the eggs a fully automated process.

Home incubators are usually small boxes (styrofoam incubators are popular) and hold a few to 50 eggs. Eggs must be turned three to five times each day, rotating at least 90 degrees. If eggs aren't turned, the embryo inside will stick to the shell and likely will be hatched with physical defects. This process is natural; hens will stand up three to five times a day and shift the eggs around with their beak.

Chickens as food

Roast Chicken

Main article: Chicken (food)

The meat of the chicken, also called "chicken," is a type of poultry. Because of its relatively low cost among meats, chicken is one of the most used meats in the world. Nearly all parts of the bird can be used for food, and the meat is cooked in many different ways around the world. Popular chicken dishes include fried chicken, chicken soup, marinated chicken wings, tandoori chicken, butter chicken, and chicken rice. Chicken is also a staple of fast food restaurants such as KFC (most products), McDonald's (chicken sandwiches/burgers, chicken nuggets) and Burger King. Chicken has a fairly neutral flavour and texture, and is used as a reference point for describing other foods; many are said to 'taste like chicken' if they are indistinctive.

Chickens as pets

A day old chick

Chickens can make loving and gentle companion animals, but can sometimes become aggressive. Some have advised against keeping certain breeds around young children, as the chickens can become territorial and violent. In Asia, chickens with striking plumage have long been kept for ornamental purposes, including feather-footed varieties such as the Cochin from Vietnam and Silkie from China and the extremely long-tailed Phoenix from Japan. Asian ornamental varieties were imported into the United States and Great Britain in the late 1800s. Distinctive American varieties of chickens have been developed from these Asian breeds. Poultry fanciers began keeping these ornamental birds for exhibition, a practice that continues today.

While some cities in the United States still allow chickens as pets, the practice is quickly disappearing. Individuals in rural communities commonly keep chickens for both ornamental and practical value. Some communities ban only roosters, allowing the quieter hens. Many zoos use chickens instead of insecticides to control insect populations.

Keeping a few chickens as backyard pets is surprisingly easy to do. The major challenge is protecting the birds from predators such as dogs, raccoons and foxes. The birds will need a secure place to sleep at night. This can be as simple or as elaborate as you like. For a few birds allowed to roam free during the day, a large doghouse-type structure with a locking door will serve just fine. Some kind of bedding such as straw or wood shavings should be provided on the floor. Nest boxes will make egg collection easier. If the birds are left in the structure during the day, a larger, more elaborate structure would be necessary.

Chickens naturally return to the same spot to roost every night. On most occasions they will put themselves to bed and your only job would be to make sure the door is shut and locked before nightfall. It is best to count the birds each night as sometimes a bird will not find his or her way back into the coop. A bird left out at night is likely to be killed by a predator.

Most chickens cannot fly well and are easily contained with 3-4' fencing. Birds which are allowed to roam the yard during the day are quite effective at controlling insects of all types. Areas of bare dirt will benefit from the weed control and soil cultivation provided by the birds in their never-ending search for food. The birds, however, will pick at plants and grass and may cause some damage to ground-cover with their scratching. Also chickens will eat most any kind of food scraps.

The eggs themselves can be quite different from the store purchased variety. Fresh yolks are quite "perky" and stand tall above the white. The yolk color is frequently a deeper color than the pale yellow of commercially raised eggs and can at times be almost a dark orange.

Growing chickens can be tamed by feeding them a special treat (such as mealworms) by hand, and by being with them for at least ten minutes daily when they are young. Even older birds can be tamed considerably by hand-feeding leftover table scraps. It can be fun to help the birds forage by turning rocks over and watching them grab worms and bugs that typically can be found in these dark, moist areas. The chickens quickly associate you with a source of food and will become your constant companion when you are both in the yard.

A former recurring skit on the weekly comedy show Saturday Night Live featured a chicken pet store with the Chinese owner (as played by Dana Carvey) not wishing to sell to customers on the basis that "Chickens make lousy house pets."

Chickens in agriculture

battery chickens

Free range chickens

File:Eggess.JPG

A free range egg (left) next to a battery egg (right).

In the United States, chickens were once raised primarily on family farms. Prior to about 1910, chicken was served primarily on special occasions or on Saturday, as the birds were typically more valued for their eggs than meat. As cities developed and markets sprung up across the nation, live chickens from local farms could often be seen for sale in crates outside the market to be butchered and cleaned onsite by the butcher. Some people still keep "free range" chickens for personal use, and may even sell the eggs and meat, but very few are raised on a large scale commercial basis this way.

With the advent of vertical integration and selective breeding of efficient meat-type birds, poultry production changed dramatically. Large farms and packing plants emerged that could grow birds by the thousands. Chickens could be sent to slaughterhouses for butchering and processing into pre-packaged commercial products to be frozen or shipped fresh to markets or wholesalers. Meat-type chickens currently grow to market weight in six to seven weeks whereas only fifty years ago it took three times as long. This is due exclusively to genetic selection and nutritional modifications (and not the use of growth hormones, which are illegal for use in poultry in the US and many other countries). Once a meat consumed only occasionally, the common availability and lower cost has made chicken a common and significant meat product within developed nations. Growing concerns over the cholesterol content of red meat in the 1980s and 1990s further resulted in increased consumption of chicken.

Another breed of chicken, the Leghorn chicken, was further developed to be an efficient egg layer. Egg production and consumption changed with the development of automation and refrigeration. Large farms were devoted solely to egg production and packaging. Today, eggs are produced on large egg ranches on which environmental parameters are well controlled. Chickens are exposed to artificial light cycles to stimulate egg production year-round. In addition, it is a common practice to induce molt through careful manipulation of light and the amount of food they receive in order to further increase egg size and production.

On average, a chicken lays one egg a day; however, this varies with the breed and time of year. For example, a Barred Plymouth Rock may lay one egg a day during the spring, summer and fall. But the same chicken may not lay at all during the winter. However, a chicken bred specifically for egg-laying may occasionally lay two eggs a day, and if housed correctly may lay all through the winter. Usually, egg laying hens are butchered after their first egg laying period that usually lasts from 12 to 14 months. The period begins when the hen is about 20 weeks old (depending on breed and season). Since roosters are not needed in the egg industry, all the males (roughly fifty percent of all chickens) are killed after their birth when producing birds for the egg industry.

Issues with mass production

Humane Treatment

Many animal welfare advocates object to killing chickens for food or to the "factory farm conditions" under which they are raised. They contend that commercial chicken production usually involves raising the birds in large, crowded rearing sheds that prevent the chickens from engaging in many of their natural behaviors. Fast food giant KFC has been the target of PETA recently due to its methods of keeping its 750 million plus chickens each year.

Chickens generally live five to eleven years depending on the breed [3]; chickens raised for meat are slaughtered prior to sexual maturity (six weeks), and thus many of the aggressive behaviors seen in adult chickens (fighting, cannibalism) are seldom seen in for-meat chickens. Both male and female chicks have the ends of their beaks cut off, to reduce the risk of them injuring each other in close quarters. Because beaks are sensitive, trimming them without anaesthesia is considered inhumane by some. It is also argued that the procedure causes life-long discomfort.

When advocating more humane treatment of chickens, it is sometimes asserted that they are intelligent. On The Tonight Show with Jay Leno, a trained chicken was shown playing "Mary Had a Little Lamb" on a toy piano and bowled 3 strikes. Animal welfare groups such as PETA regard such cases as evidence that the birds are intelligent.[4] Dr. Chris Evans of Macquarie University claims that their range of 20 calls, problem solving skills and the ability to recognise each other by facial features demonstrate the intelligence of chickens, saying "As a trick at conferences, I sometimes list these attributes, without mentioning chickens, and people think I’m talking about monkeys." [5]

Another animal welfare issue is the use of selective breeding to create heavy, large-breasted birds, which can lead to crippling leg disorders and heart failure for some of the birds. Concerns have been raised that companies growing single varieties of bird for eggs or meat are increasing their susceptiblity to disease. For this reason, many scientists are promoting the conservation of heritage breeds to retain genetic diversity in the species.

In 2004, 8.9 billion chickens were slaughtered in the United States.[6]

Human Concerns

Antibiotics

Because raising chickens in close quarters fosters the spread of disease, factory farms use antibiotics as a matter of course; many contend that this puts humans at risk as bacterial strains develop stronger and stronger resistances.[7]

A proposed bill in the American congress would make the use of antibiotics in animal feed legal only for therapeutic (rather than preventative) use, but it has not been passed yet. [8] Though this will certainly solve one problem, it does not address the fact that bacteria continue to develop resistances; hence, there is the risk of slaughtered chickens harboring these bacteria and passing them on to the humans that consume them.

In October 2000, the FDA discovered that two antibiotics were no longer effective in treating diseases found in factory-farmed chickens; one antibiotic was willingly and swiftly pulled from the market, but the other, Baytril was not. Bayer, the company which produced it, contested the claim and as a result, Baytril remained in use until July of 2005.[9]

Arsenic

Chickens feed can also include Roxarsone, an antimicrobial drug that also promotes growth. The drug has generated controversy because it contains the element arsenic, which can cause cancer, dementia, and neurological problems in humans. Yet the arsenic in Roxarsone is not of the type which has been linked to cancer. A Consumer Reports study in 2004 reported finding "no detectable arsenic in our samples of muscle" but found "A few of our chicken-liver samples has an omount that according to EPA standards could cause neurological problems in a child who ate 2 ounces of cooked liver per week or in an adult who ate 5.5 ounces per week." However, the Food and Drug Administration (FDA) not the Environmental Protection Agency (EPA) is responsible for the regulation of foods and all samples tested were "far less than the... amount allowed in a food product."[10]

Growth Hormones

Chickens grow much more rapidly than they once did and some consumers have concluded that this rapid growth is due to the use of hormones in these animals. Some consumers believe that the increasingly earlier onset of puberty is the result of the liberal use of such hormones. However, hormone use in poultry production is illegal in the United States. No chicken meat for sale in Australia is fed hormones. Furthermore, several scientific studies have documented the fact that chickens grow rapidly because they are bred to do so. Perhaps a small producer of natural and organic chickens said it best:

If this were 1948, you might have something to worry about. Using hormones to boost egg production was a brief fad in the Forties, but was abandoned because it didn't work. Using hormones to produce soft-meated roasters was used to some extent in the Forties and Fifties, but the increased growth rates of broilers made the practice irrelevant--the broilers got as big as anyone wanted them to get when they were still young enough to be soft-meated without chemicals.

The only hormone that was ever used in any quantity on poultry (DES) was banned in 1959, after everyone but a few die-hard farmers had given them up as a silly idea. Hormones are now illegal in poultry and eggs. The people who advertise "No hormones" are either woefully ignorant or are indulging in cynical fear-mongering, maybe both.

E.coli

According to Consumer Reports, "1.1 million or more Americans [are] sickened each year by undercooked, tainted chicken." A USDA study discovered E.Coli in 99% of supermarket chicken, the result of chickens being raised in their own feces. Though E. Coli can usually be killed by proper cooking times, there is still some risk associated with it, and its near-ubiquity in commercially-farmed chicken is troubling to some.

Avian Flu

There is also a risk that the crowded conditions in many chicken farms will allow avian flu to spread quickly. A United Nations press release states: "Governments, local authorities and international agencies need to take a greatly increased role in combating the role of factory-farming, commerce in live poultry, and wildlife markets which provide ideal conditions for the virus to spread and mutate into a more dangerous form..."[11]

Efficiency Issues

Farming of chickens on an industrial scale relies on high protein feeds derived from the soybean. The soybean is also a complete protein source for humans. Giving the feed to chickens means the nutrients in the feed reach humans with a much lower efficiency than through direct consumption of soybean products.

Chicken diseases

Baby chicks in a box

Chickens are susceptible to parasites, including lice, mites, ticks, fleas, and intestinal worms as well as many other diseases. (Despite the name, they are not affected by Chickenpox; it is a disease of humans, not chickens.)

Some of the common diseases that affect chickens are shown below:

Name	Common Name	Caused by
Aspergillosis		fungi
Avian influenza	bird flu	virus
Histomoniasis	Blackhead disease	virus
Botulism		toxin
Cage Layer Fatigue		small cage
Coccidiosis		parasites
Colds		virus
Crop Bound		improper feeding
Egg bound		oversized egg
Erysipelas		bacteria
Fatty Liver Hemorrhagic Syndrome		high-energy food
Fowl Cholera		bacteria
Fowl pox		virus
Fowl Typhoid		bacteria
Gallid herpesvirus 1 or Infectious Laryngotracheitis		virus
Gapeworms	Syngamus trachea	worms
Infectious Bronchitis		virus
Infectious Bursal Disease	Gumboro	virus
Infectious Coryza		bacteria
Lymphoid Leucosis
Marek's disease		virus
Moniliasis	Yeast Infection or Thrush	fungi
Mycoplasmas		bacteria-like organisms
Newcastle disease		virus
Necrotic Enteritis		bacteria
Omphalitis	Mushy chick disease	umbilical cord stump
Prolapse
Psittacosis		bacteria
Pullorum	Salmonella	bacteria
Scaly leg		parasites
Squamous cell carcinoma		cancer
Tibial dyschondroplasia		speed growing
Toxoplasmosis		parasites
Ulcerative Enteritis		bacteria

Chickens in religion

Chickens, Indonesia

In Indonesia the chicken has great significance during the Hindu cremation ceremony. A chicken is a channel for evil spirits which may be present during the ceremony. A chicken is tethered by the leg and kept present at the ceremony for the duration to ensure that any evil spirits present during the ceremony go into the chicken and not the family members present. The chicken is then taken home and returns to its normal life. He or she is not treated in any special way or slaughtered after the ceremony.

In ancient Greece, the chicken was not normally used for sacrifices, perhaps because it was still considered an exotic animal. Because of its valour, cocks are found as attributes of Ares, Heracles and Athena. The alleged last words of Socrates as he died from hemlock poisoning, as recounted by Plato, were "Crito, I owe a cock to Asclepius; will you remember to pay the debt?", signifying that death was a cure for the illness of life.

The Greeks believed that even lions were afraid of cocks. Several of Aesop's Fables reference this belief. In the cult of Mithras, the cock was a symbol of the divine light and a guardian against evil.

In the Bible, Jesus prophesied the betrayal by Peter: "And he said, I tell thee, Peter, the cock shall not crow this day, before that thou shalt thrice deny that thou knowest me." (Luke 22:43) Thus it happened (Luke 22:61), and Peter cried bitterly. This made the cock a symbol for both vigilance and betrayal.

Earlier, Jesus compares himself to a mother hen, when talking about Jerusalem: "How often would I have gathered thy children together, even as a hen gathereth her chickens under her wings, and ye would not!" (Matthew 23:37; also Luke 13:34).

In many Central European folk tales, the devil is believed to flee at the first crowing of a cock.

In traditional Jewish practice, a chicken is swung around the head and then slaughtered on the afternoon before Yom Kippur, the Day of Atonement, in a ritual called kapparos. The sacrifice of the chicken is to receive atonement, for the bird takes on all the person's sins in kapparos. The meat is then donated to the poor. A woman brings a hen for the ceremony, while a man brings a rooster. Although not actually a sacrifice in the biblical sense, the death of the chicken reminds the penitent sinner that his or her life is in God's hands.

The Talmud speaks of learning "courtesy toward one's mate" from the rooster. This might refer to the fact that, when a rooster finds something good to eat, he calls his hens to eat first.

The chicken is one of the Zodiac symbols of the Chinese calendar. Also in Chinese religion, a cooked chicken as a religious offering is usually limited to ancestor veneration and worship of village deities. Vegetarian deities such as the Buddha are not one of the recipients of such offerings. Under some observations, an offering of chicken is presented with "serious" prayer (while roasted pork is offered during a joyous celebration). In Confucian Chinese Weddings, a chicken can be used as a substitute for one who is seriously ill or not available (e.g sudden death) to attend the ceremony. A red silk scarf is placed on the chicken's head and a close relative of the absent bride/groom holds the chicken so the ceremony may proceed. However, this practice is rare today.

History

Hen with newly hatched chicks

The first pictures of chickens in Europe are found on Corinthian pottery of the 7th century BC. The poet Cratinus (mid-5th century BC, according to the later Greek author Athenaeus) calls the chicken "the Persian alarm". In Aristophanes's comedy The Birds (414 BC) a chicken is called "the Median bird", which points to an introduction from the East. Pictures of chickens are found on Greek red figure and black-figure pottery.

In ancient Greece, chickens were still rare and were a rather prestigious food for symposia. Delos seems to have been a centre of chicken breeding.

An early domestication of chickens in Southeast Asia is probable, since the word for domestic chicken (*manuk) is part of the reconstructed Proto-Austronesian language (see Austronesian languages). Chickens, together with dogs and pigs, were the domestic animals of the Lapita culture, the first Neolithic culture of Oceania.

Chickens were spread by Polynesian seafarers and reached Easter Island in the 12th century AD, where they were the only domestic animal, with the possible exception of the Polynesian Rat (Rattus exulans). They were housed in extremely solid chicken coops built from stone. Traveling as cargo on trading boats, they reached the Asian continent via the islands of Indonesia and from there spread west to Europe and western Asia.

Chickens in ancient Rome

The Romans used chickens for oracles, both when flying ("ex avibus") and when feeding ("auspicium ex tripudiis"). The hen ("gallina") gave a favourable omen ("auspicium ratum"), when appearing from the left (Cic.,de Div. ii.26), like the crow and the owl.

For the oracle "ex tripudiis" according to Cicero (Cic. de Div. ii.34), any bird could be used, but normally only chickens ("pulli") were consulted. The chickens were cared for by the pullarius, who opened their cage and fed them pulses or a special kind of soft cake when an augury was needed. If the chickens stayed in their cage, made noises ("occinerent"), beat their wings or flew away, the omen was bad; if they ate greedily, the omen was good.

In 249 BC, the Roman general Publius Claudius Pulcher had his chickens thrown overboard when they refused to feed before the battle of Drepana, saying "If they won't eat, perhaps they will drink." He promptly lost the battle against the Carthaginians and 93 Roman ships were sunk. Back in Rome, he was tried for impiety and heavily fined.

In 161 BC a law was passed in Rome that forbade the consumption of fattened chickens. It was renewed a number of times, but does not seem to have been successful. Fattening chickens with bread soaked in milk was thought to give especially delicious results. The Roman gourmet Apicius offers 17 recipes for chicken, mainly boiled chicken with a sauce. All parts of the animal are used: the recipes include the stomach, liver, testicles and even the pygostyle (the fatty "tail" of the chicken where the tail feathers attach).

The Roman author Columella gives advice on chicken breeding in his eighth book of his treatise on agriculture. He identifies Tanagrian, Rhodic, Chalkidic and Median (commonly misidentified as Melian) breeds, which have an impressive appearance, a quarrelsome nature and were used for cockfighting by the Greeks. For farming, native (Roman) chickens are to be preferred, or a cross between native hens and Greek cocks. Dwarf chickens are nice to watch because of their size but have no other advantages.

Per Columella, the ideal flock consists of 200 birds, which can be supervised by one person if someone is watching for stray animals. White chickens should be avoided as they are not very fertile and are easily caught by eagles or goshawks. One cock should be kept for five hens. In the case of Rhodian and Median cocks that are very heavy and therefore not much inclined to sex, only three hens are kept per cock. The hens of heavy fowls are not much inclined to brood; therefore their eggs are best hatched by normal hens. A hen can hatch no more than 15-23 eggs, depending on the time of year, and supervise no more than 30 hatchlings. Eggs that are long and pointed give more male, rounded eggs mainly female hatchlings.

Per Columella, Chicken coops should face southeast and lie adjacent to the kitchen, as smoke is beneficial for the animals. Coops should consist of three rooms and possess a hearth. Dry dust or ash should be provided for dust-baths.

According to Columella, chicken should be fed on barley groats, small chick-peas, millet and wheat bran, if they are cheap. Wheat itself should be avoided as it is harmful to the birds. Boiled ryegrass (Lollium sp.) and the leaves and seeds of alfalfa (Medicago sativa L.) can be used as well. Grape marc can be used, but only when the hens stop laying eggs, that is, about the middle of November; otherwise eggs are small and few. When feeding grape marc, it should be supplemented with some bran. Hens start to lay eggs after the winter solstice, in warm places around the first of January, in colder areas in the middle of February. Parboiled barley increases their fertility; this should be mixed with alfalfa leaves and seeds, or vetches or millet if alfalfa is not at hand. Free-ranging chickens should receive two cups of barley daily.

Columella advises farmers to slaughter hens that are older than three years, because they no longer produce sufficient eggs. Capons were produced by burning out their spurs with a hot iron. The wound was treated with potter's chalk.

For the use of poultry and eggs in the kitchens of ancient Rome see Roman eating and drinking.

Chickens in South America

Unless tamed, chickens will naturally nest in trees.

An unusual variety of chicken that has its origins in South America is the araucana. Araucanas, some of which are tailless and some of which have tufts of feathers around their ears, lay blue-green eggs. As J. Gongora reports, some people have suggested that they predate the arrival of European chickens brought by the Spanish and are evidence of pre-Columbian trans-pacific contacts between Asia and South America. (J. Gongora, et al., "Mitochondrial DNA sequences reveal a putative East Asian ancestry for old Chilean chickens," Proceedings of the International Conference on Animal Genetics, ISAG 2006, Porto Seguro, BA, Brasil.)

Chicken breeds

Main article: List of chicken breeds

Chickens in popular culture

Main article: Chickens in popular culture

Mythical chickens and part-chicken creatures

Main article: Mythological things at least in part based on chickens

Chickens as symbols and mascots

Main article: Symbolic chickens

See also

• Chicken hypnotism
• List of chicken breeds
• The chicken or the egg
• Why did the chicken cross the road?
• Rubber chicken
• Gamebird hybrids - hybrids between chickens, peafowl, guineafowl and pheasants
• Chook raffle - A type of raffle where the prize is a chicken.

References

P. Smith, The Chicken Book (University of Georgia Press, 2000), passim.

External links

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