Chicken
Archaeologists uncovered chicken bones at Ban Non Wat in central Thailand dating back 3,250 years. These skeletal remains sit alongside rice grains that wild junglefowl likely consumed during bamboo seeding cycles. A 2020 study published in Nature analyzed DNA from 863 chickens across the globe to trace their origins. The research points to a single domestication event occurring roughly 8,000 years ago within Southeast Asia. Humans took advantage of the red junglefowl's ability to reproduce prolifically when exposed to abundant food supplies. This genetic lineage shares between 71 and 79 percent of its genome with modern domestic birds.
The Proto-Austronesian language contains the word manuk for the domestic chicken, indicating ancient ownership by these peoples. Prehistoric Austronesian maritime migrations carried chickens throughout Island Southeast Asia starting from at least 3000 BC. Dogs and pigs traveled alongside them on voyages reaching Micronesia, Polynesia, and Madagascar. Blue-egged chickens found only in the Americas suggest an Asian origin for early American populations. Chicken bones from the Arauco Peninsula in south-central Chile were radiocarbon dated as pre-Columbian. Further study of those same bones cast doubt on findings regarding their connection to Polynesian seafarers.
Thorleif Schjelderup-Ebbe described the concept of dominance involving pecking in female chickens during 1921. Individual chickens dominate others to establish a hierarchy that dictates access to food and nest sites. A male rooster may dance in a circle around or near a hen to initiate courting rituals. The dance triggers a response where the hen crouches if she is receptive to mating. Hens cluck loudly after laying an egg to call their chicks toward food sources. Chickens give different warning calls to indicate that a predator approaches from the air or on the ground.
More than 50 billion chickens are reared annually as a source of meat and eggs worldwide. The Worldwatch Institute reports that 74 percent of global poultry meat comes from factory farms. Broiler breeds typically take less than six weeks to reach slaughter size under intensive systems. Hens from battery cage systems sometimes lose significant amounts of feathers and have life expectancy reduced to less than two years. In the United States, more than 8 billion chickens were slaughtered each year for meat consumption. Some flocks undergo force-moulting procedures involving complete withdrawal of food for seven to fourteen days.
Scientists completed the sequencing of the chicken genome at 1.21 Gb in the early 2000s. This final gene set contained 26,640 genes including noncoding elements and pseudogenes. Researchers switched on a recessive gene called talpid2 in 2006 to study embryonic jaw formation. The embryo jaws initiated formation of teeth similar to those found in ancient bird fossils. Large numbers of embryos can be provided commercially to observe developing biological structures. Fertilized eggs open easily for experiments before being closed again to study later developmental effects.
Roosters are used for divination practices known as alectryomancy during ritual cockfights. Gabriel García Márquez published One Hundred Years of Solitude in 1967 featuring a town where cockfighting was outlawed. The pseudo-riddle asking why the chicken crossed the road dates back to 1847 or earlier. Adriaen van Utrecht created Turkeys and Chickens artwork in 1646 depicting farmyard scenes. Walter Osborne painted Feeding the Chickens in 1885 showing rural life interactions. The nursery rhyme Cock a Doodle Doo appeared in Mother Goose's Melody published in 1765.
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Common questions
When and where were the earliest chicken bones discovered?
Archaeologists uncovered chicken bones at Ban Non Wat in central Thailand dating back 3,250 years. These skeletal remains sit alongside rice grains that wild junglefowl likely consumed during bamboo seeding cycles.
How many years ago did the single domestication event of chickens occur?
A 2020 study published in Nature analyzed DNA from 863 chickens across the globe to trace their origins. The research points to a single domestication event occurring roughly 8,000 years ago within Southeast Asia.
What percentage of its genome do modern domestic birds share with red junglefowl?
This genetic lineage shares between 71 and 79 percent of its genome with modern domestic birds. Humans took advantage of the red junglefowl's ability to reproduce prolifically when exposed to abundant food supplies.
Which year was the concept of dominance involving pecking described for female chickens?
Thorleif Schjelderup-Ebbe described the concept of dominance involving pecking in female chickens during 1921. Individual chickens dominate others to establish a hierarchy that dictates access to food and nest sites.
When were scientists able to complete the sequencing of the chicken genome?
Scientists completed the sequencing of the chicken genome at 1.21 Gb in the early 2000s. This final gene set contained 26,640 genes including noncoding elements and pseudogenes.