Misplaced Pages

This is an old revision of this page, as edited by 209.158.4.142 (talk) at 20:12, 18 August 2008 (→Chickens in agriculture). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Template:Two other uses

Chicken
A cock (left) and hen (right) roosting together
Conservation status
Domesticated
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Galliformes
Family:	Phasianidae
Genus:	Gallus
Species:	G. gallus
Binomial name
Gallus gallus (Linnaeus, 1758)
Synonyms
Gallus gallus domesticus

The chicken (Gallus gallus, sometimes G. gallus domesticus) is a domesticated fowl likely descended from the wild Indian and southeast Asian Red Junglefowl (Gallus gallus) and the related Grey Junglefowl (G. sonneratii). Traditionally it has been widely accepted that the chicken was descended solely from the former, as hybrids of both wild types tended toward sterility; but recent genetic work has revealed that the genotype for yellow skin present in the domestic fowl is not present in what is otherwise its closest kin, the Red Junglefowl. It is deemed most likely, then, that the yellow skin trait in domestic birds originated in the Grey Junglefowl.

The chicken is one of the most common and widespread domestic animals. With a population of more than 24 billion in 2003, there are more chickens in the world than any other bird. Humans keep chickens primarily as a source of food, with both their meat and their eggs consumed.

Chickens as food

The meat of the chicken, also called "chicken," is a type of poultry meat. Because of its relatively low cost, 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 can be cooked in many different ways. Popular chicken dishes include fried chicken, chicken soup, Buffalo wings, tandoori chicken, butter chicken, and chicken rice. Chicken is also a staple of fast food restaurants. Commercially produced chicken usually has a fairly neutral flavor and texture, and is used as a reference point for describing other foods; many are said to "taste like chicken" if they are indistinctive. Many people choose not to eat chicken as part of a vegetarian lifestyle.

Issues with mass production

Humane treatment

Animal welfare groups have frequently targeted the poultry industry for engaging in practices which they believe to be inhumane. Many animal welfare advocates object to killing chickens for food, the "factory farm conditions" under which they are raised, methods of transport, and slaughter. PETA and other groups have repeatedly conducted undercover investigations at chicken farms and slaughterhouses which they allege confirm their claims of cruelty.

Laying hens are routinely debeaked to prevent fighting. Because beaks are sensitive, trimming them without anaesthesia is considered inhumane by some. It is also argued that the procedure causes life-long discomfort. Conditions in intensive chicken farms may be unsanitary, allowing the proliferation of diseases such as salmonella and E coli. Chickens may be raised in total darkness. Rough handling and crowded transport during various weather conditions and the failure of existing stunning systems to render the birds unconscious before slaughter have also been cited as welfare concerns.

Another animal welfare concern 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 birds for eggs or meat are increasing their susceptibility to disease.

Some groups who advocate for more humane treatment of chickens, claim that they are intelligent. Dr. Chris Evans of Macquarie University claims that their range of 20 calls, problem solving skills, use of representational signalling, and the ability to recognize each other by facial features demonstrate the intelligence of chickens..

In 2004, 8.9 billion chickens were slaughtered in the United States. There is no federal law that regulates the humane treatment of chickens.

Human concerns

Antibiotics

Antibiotics have been used on poultry in large quantities since the Forties, when it was found that the byproducts of antibiotic production, fed because the antibiotic-producing mold had a high level of vitamin B12 after the antibiotics were removed, produced higher growth than could be accounted for by the vitamin B12 alone. Eventually it was discovered that the trace amounts of antibiotics remaining in the byproducts accounted for this growth.

The mechanism is apparently the adjustment of intestinal flora, favoring "good" bacteria while suppressing "bad" bacteria, and thus the goal of antibiotics as a growth promoter is the same as for probiotics. Because the antibiotics used are not absorbed by the gut, they do not put antibiotics into the meat or eggs.

Antibiotics are used routinely in poultry for this reason, and also to prevent and treat disease. Many contend that this puts humans at risk as bacterial strains develop stronger and stronger resistances. Critics point out that, after six decades of heavy agricultural use of antibiotics, opponents of antibiotics must still make arguments about theoretical risks, since actual examples are hard to come by. Those antibiotic-resistant strains of human diseases whose origin is known originated in hospitals rather than farms.

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. However, this may present the risk of slaughtered chickens harboring pathogenic bacteria and passing them on to 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 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 2005.

Arsenic

Chicken 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 amount 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) is the organization responsible for the regulation of foods in America, and all samples tested were "far less than the... amount allowed in a food product."

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 in humans is the result of the liberal use of such hormones. However, hormone use in poultry production is illegal in the United States. Similarly, 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. A small producer of natural and organic chickens confirmed this assumption:

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 sickened each year by undercooked, tainted chicken." A USDA study discovered E. coli in 99% of supermarket chicken, the result of chicken butchering not being a sterile process. Feces tend to leak from the carcass until the evisceration stage, and the evisceration stage itself gives an opportunity for the interior of the carcass to receive intestinal bacteria. (So does the skin of the carcass, but the skin presents a better barrier to bacteria and reaches higher temperatures during cooking). Before 1950, this was contained largely by not eviscerating the carcass at the time of butchering, deferring this until the time of retail sale or in the home. This gave the intestinal bacteria less opportunity to colonize the edible meat. The development of the "ready-to-cook broiler" in the 1950s added convenience while introducing risk, under the assumption that end-to-end refrigeration and thorough cooking would provide adequate protection. E. coli can be killed by proper cooking times, but there is still some risk associated with it, and its near-ubiquity in commercially-farmed chicken is troubling to some. Irradiation has been proposed as a means of sterilizing chicken meat after butchering.

Avian influenza

There is also a risk that the crowded conditions in many chicken farms will allow avian influenza 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..."

Efficiency

Farming of chickens on an industrial scale relies largely on high protein feeds derived from soybeans; in the European Union the soybean dominates the protein supply for animal feed, and the poultry industry is the largest consumer of such feed. Giving the feed to chickens means the protein reaches humans with a much lower efficiency than through direct consumption of soybean products. Some nutrients, however, are present in chicken but not in the soybean.

Genetic Pollution

One other major problem concerns the wild Red Junglefowl. Feral populations of domestic birds may stray across the ranges of the wild Junglefowl species, it has created a concern of genetic pollution. Wild Junglefowl should have an eclipse plumage but apparently some males lack such a plumage, indicating hybridisation with the domestic chicken. Further confusing the issue of hybrids is that the domestic chicken itself is a hybrid between the Red and Grey Junglefowl. It has even been suggested that pure populations of Red Junglefowl may already be extinct.

Chicken diseases

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

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

Chickens in religion

In Islam, The Messenger of Allah said, "When you hear the crowing of cocks, ask for Allah's Blessings for (their crowing indicates that) they have seen an angel. And when you hear the braying of donkeys, seek Refuge with Allah from Satan for (their braying indicates) that they have seen a Satan." Sahih Al-Bukhari Vol. 4, Book 54, Number 522: Narrated Abu Huraira.

In Indonesia the chicken has great significance during the Hindu cremation ceremony. A chicken is considered 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 its 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.

In ancient Greece, the chicken was not normally used for sacrifices, perhaps because it was still considered an exotic animal. Because of its valour, the cock is found as an attribute 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 New Testament, Jesus prophesied the betrayal by Peter: "Jesus answered, 'I tell you, Peter, before the rooster crows today, you will deny three times that you know me.'" (Luke 22:34) 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: "O Jerusalem, Jerusalem, you who kill the prophets and stone those sent to you, how often I have longed to gather your children together, as a hen gathers her chicks under her wings, but you were not willing." (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.

Chickens in history

The first pictures of chickens in Europe are found on Corinthian pottery of the 7th century BCE. The poet Cratinus (mid-5th century BCE, according to the later Greek author Athenaeus) calls the chicken "the Persian alarm". In Aristophanes's comedy The Birds (414 BCE) 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 BCE, 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.

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 BCE, 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 BCE 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

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. It has long been suggested that they predate the arrival of European chickens brought by the Spanish and are evidence of pre-Columbian trans-Pacific contacts between Asian or Pacific Oceanic peoples, particularly the Polynesians and South America. In 2007, an international team of researchers reported the results of analysis of chicken bones found on the Arauco Peninsula in south central Chile. Radiocarbon dating indicated that the chickens were Pre-Columbian, and DNA analysis showed that they were related to prehistoric populations of chickens in Polynesia. These results appear to confirm that the chickens came from Polynesia and that there were transpacific contacts between Polynesia and South America before Columbus's arrival in the Americas.

See also

• American Poultry Association
• Alektorphobic - someone scared of chickens
• List of chicken breeds
• Chicken coop
• Symbolic chickens
• Chicken hypnotism
• 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.
• Exploding chicken
• Chicken fat

References

Cited

1. Eriksson J, Larson G, Gunnarsson U, Bed'hom B, Tixier-Boichard M, et al. (2008) Identification of the Yellow Skin Gene Reveals a Hybrid Origin of the Domestic Chicken. PLoS Genet January 23, 2008 .
2. according to Firefly Encyclopedia of Birds, Ed. Perrins, Christopher. Buffalo, N.Y.: Firefly Books, Ltd., 2003.
3. Kentucky Fried Cruelty :: Undercover Investigations :: Compassion Over Killing Investigation
4. HTML Redirect
5. Ewing, Poultry Nutrition, 5th ed., 1963, p. 1283.
6. Ewing, Poultry Nutrition, 5th ed., 1963, p. 1284.
7. http://dwb.unl.edu/Teacher/NSF/C10/C10Links/www.sierraclub.org/cafos/toolkit/antibiotic.asp
8. ^ http://www.consumerreports.org/cro/food/animal-feed-and-the-food-supply-105/chicken-arsenic-and-antibiotics/index.htm
9. Baytril: FDA Bans Bayer Antibiotic for Poultry Use RANDY FABI / Reuters 29jul2005
10. "The Use Of Steroid Hormones For Growth Promotion In Food-Producing Animals"
11. Landline - 5/05/2002: Challenging food safety myths . Australian Broadcasting Corp
12. Carcass composition and yield of 1957 versus 2001 broilers when fed representative 1957 and 2001 broiler diets - Havenstein et al. 82 (10): 1509 - Poultry Science
13. Carcass composition and yield of 1991 vs 1957 broi...[Poult Sci. 1994] - PubMed Result
14. http://www.farmsanctuary.org/newsletter/Avain_flu.htm
15. ^ Protein Sources For The Animal Feed Industry
16. DNA reveals how the chicken crossed the sea Brendan Borrell, Nature, 5 June 2007. Retrieved 2007-10-01.
17. A. A. Storey et al, "Radiocarbon and DNA evidence for a pre-Columbian introduction of Polynesian chickens to Chile,"Proceedings of the National Academy of Sciences of the United States of America, www.pnas.org/cgi/doi/10.1073/pnas.0703993104; John Noble Wilford, "First Chickens in Americas were Brought from Polynesia, New York Times, June 5, 2007

General

• Smith, Page (April 2000). The Chicken Book. University of Georgia Press. ISBN 082032213X. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

External links

• Domesticated animals
• Chicken
• Junglefowls
• United States state birds