Chicken
The concept of dominance, involving pecking, was described in female chickens by Thorleif Schjelderup-Ebbe in 1921 as the “pecking order”. Individual chickens dominate others, establishing a pecking order; dominant individuals take priority for access to food and nest sites. Chickens are primarily kept for their meat and eggs, though they are also kept as pets. In situations where one adult bird challenges another—which happens most often when a new bird is introduced into the flock—fights involving males risk injury and death more often than fights involving females. In groups of male chicks, however, fights for dominance may continue into adulthood.
- It is estimated that chickens share between 71 and 79% of their genome with red junglefowl.
- Chickens have been thought of primarily as providers of food, but their cognition, emotions, and sociality are comparable with other birds and mammals.
- Chicken, (Gallus gallus), any of more than 60 breeds of medium-sized poultry that are primarily descended from the wild red jungle fowl (Gallus gallus, family Phasianidae, order Galliformes) of India.
- The body is round, the legs are unfeathered in most breeds, and the wings are short.
Chicken can mean a chick, and this was historically the meaning of the word chicken, as in William Shakespeare’s play Macbeth, where Macduff laments the death of “all my pretty chickens and their dam”. As of 2023, the global chicken population exceeds 26.5 billion, with more than 50 billion birds produced annually for consumption. It was first domesticated around 8,000 years ago and is one of the most common and widespread domesticated animals in the world.
Farming
Chicks are born covered in down, but they mature quickly, becoming fully feathered after four to five weeks. Fertilized embryos develop quickly, and chicks hatch approximately 21 days later. There is khelaghor-bangladesh.com/bd some debate about what the chicken’s scientific name should be.
Keeping chickens as pets became increasingly popular in the 2000s among urban and suburban residents. The first pictures of chickens in Europe are found on Corinthian pottery of the 7th century BC. Phoenicians spread chickens along the Mediterranean coasts as far as Iberia. These chickens may have been introduced during pre-Columbian times to South America via Polynesian seafarers, but this is disputed. Skeletons of birds in the Gallus genus were used as grave goods at the site, confirming domestication. The chicks imprint on the hen and subsequently follow her continually.
Africa
Egg laying is stimulated by the long stretches of daylight that occur during the warmer months; however, artificial lights placed in chicken coops can trigger a hen’s egg laying response throughout the year. Males (called cocks or roosters) and females (hens) are known for their fleshy combs, lobed wattles hanging below the bill, and high-arched tails. In the process of domestication, chickens were apparently kept initially for cockfighting, and only later used for food. Many people obtain chickens for their egg production but often name them and treat them as any other pet like cats or dogs. Genetic sequencing of chicken bones from archaeological sites in Europe revealed that in the High Middle Ages chickens became less aggressive and began to lay eggs earlier in the breeding season. The possibility that domestic chickens were in the Americas before Western contact is debated by researchers, but blue-egged chickens, found only in the Americas and Asia, suggest an Asian origin for early American chickens.
Under natural conditions, most birds lay only until a clutch is complete; they then incubate all the eggs. Adult chickens of both sexes have a fleshy crest on their heads called a comb or cockscomb, and hanging flaps of skin on either side under their beaks called wattles; combs and wattles are more prominent in males. In older sources, and still often in trade and scientific contexts, chickens as a species are described as common fowl or domestic fowl.
It is estimated that chickens share between 71 and 79% of their genome with red junglefowl. Domesticated chickens freely interbreed with populations of red junglefowl. Strongly inbred Langshan chickens display obvious inbreeding depression in reproduction, particularly for traits such as age when the first egg is laid and egg number. Only hens that could no longer produce enough eggs were killed and sold for meat. Only in the early 20th century, however, did chicken meat and eggs become mass-production commodities.
Breeding increased under the Roman Empire and reduced in the Middle Ages. Middle Eastern chicken remains go back to a little earlier than 2000 BC in Syria. Chickens reached Egypt via the Middle East for purposes of cockfighting about 1400 BC and became widely bred in Egypt around 300 BC. Re-examination of bones from over 600 sites, and dating of those from 23 sites, identified the earliest probable chicken bones as from central Thailand, at Ban Non Wat, some 3,250 years ago.