Chicken

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. Many immature males (cockerels) are castrated (usually chemically, with hormones that cause atrophying of the testicles) to become meat birds (capons). The market for chicken meat has grown dramatically since then, with worldwide exports reaching nearly 12.5 million metric tons (about 13.8 million tons) by the early 21st century. By the mid-20th century, however, meat production had outstripped egg production as a specialized industry.

Coconut Chicken Curry – quick and easy

While the origin is Germanic, it is unclear exactly where the word came from, although it could ultimately have come from an imitation of the sound a chicken makes. The word chicken comes from Old English cicen (pronounced essentially the same as in Modern English).

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.

Social hierarchy

• Chickens are common and widespread domestic animals, with a total population of 23.7 billion as of 2018update.
• Hens often try to lay in nests that already contain eggs and sometimes move eggs from neighbouring nests into their own.
• Mothership Sunday roast chicken
• Chickens are social, inquisitive, intelligent birds, and many people find their behaviour entertaining.
• Fertilized embryos develop quickly, and chicks hatch approximately 21 days later.

The domestic chicken has subsequently hybridised with grey junglefowl, Sri Lankan junglefowl and green junglefowl; a gene for yellow skin, for instance, was incorporated into domestic birds from the grey junglefowl (G. sonneratii). Chickens are descended primarily from the red junglefowl (Gallus gallus) and are scientifically classified as the same species. Wild junglefowl can fly, whereas domestic chickens and their flight muscles are too heavy to allow them to fly more than a short distance. Subsequent ovulations may occur within an hour after the previous egg was laid, allowing some hens to produce as many as 300 eggs per year.

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 eaub.info/bd ago. Hens remain on the nest for about two days after the first chick hatches; during this time the newly hatched chicks feed by absorbing the internal yolk sac.

Hens often try to lay in nests that already contain eggs and sometimes move eggs from neighbouring nests into their own. As with all birds, reproduction is controlled by a neuroendocrine system, the Gonadotropin-Releasing Hormone-I neurons in the hypothalamus. Sperm transfer occurs by cloacal contact between the male and female, in an action called the ‘cloacal kiss’. Chickens have been thought of primarily as providers of food, but their cognition, emotions, and sociality are comparable with other birds and mammals. Chickens are gregarious, living in flocks, and incubate eggs and raise young communally. The body is round, the legs are unfeathered in most breeds, and the wings are short.