The chicken (Gallus gallus domesticus) is a domesticated subspecies of the red junglefowl (Gallus gallus), originally native to Southeast Asia. It was first domesticated around 8,000 years ago and is one of the most common and widespread domesticated animals in the world. Chickens are primarily kept for their meat and eggs, though they are also kept as pets.
As of 2023, the global chicken population exceeds 26.5 billion, with more than 50 billion birds produced annually for consumption. Specialized breeds such as broilers and laying hens have been developed for meat and egg production, respectively. A hen bred for laying can produce over 300 eggs per year. Chickens are social animals with complex vocalizations and behaviors, and feature in folklore, religion, and literature across many societies. Their economic importance makes them a central component of global animal husbandry.

Biddy: a chicken, or a newly hatched chicken
Capon: a castrated or neutered male chicken
Chick: a young chicken
Chook /tʃʊk/: a chicken (Australia/New Zealand, informal)
♥♥♥♥: a fertile adult male chicken
Cockerel: a young male chicken
Hen: an adult female chicken
Pullet: a young female chicken less than a year old. In the poultry industry, a pullet is a sexually immature chicken less than 22 weeks of age.
Rooster: a fertile adult male chicken, especially in North America. Originated in the 18th century, possibly as a euphemism to avoid the sexual connotation of the word ♥♥♥♥.
Yardbird: a chicken (southern United States, dialectal)
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". The usage is preserved in placenames such as the Hen and Chicken Islands. In older sources, and still often in trade and scientific contexts, chickens as a species are described as common fowl or domestic fowl.

Chickens are relatively large birds, active by day. The body is round, the legs are unfeathered in most breeds, and the wings are short. Wild junglefowl can fly, whereas domestic chickens and their flight muscles are too heavy to allow them to fly more than a short distance. Size and coloration vary widely between breeds. Newly hatched chicks of both modern and heritage varieties weigh the same, about 37g (1.3oz). Modern varieties however grow much faster; by day 35 a Ross 708 broiler may weigh 1.8 kg (4.0lb) as against the 1.05 kg (2.3lb) of a heritage chicken of the same age.
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. Some breeds have a mutation that causes extra feathering under the face, giving the appearance of a beard.
Chickens are omnivores. In the wild, they scratch at the soil to search for seeds, insects, and animals as large as lizards, small snakes, and young mice. A chicken may live for 5–10 years, depending on the breed. The world's oldest known chicken lived for 16 years.
Chickens are gregarious, living in flocks, and incubate eggs and raise young communally. Individual chickens dominate others, establishing a pecking order; dominant individuals take priority for access to food and nest sites. The concept of dominance, involving pecking, was described in female chickens by Thorleif Schjelderup-Ebbe in 1921 as the "pecking order". Male chickens tend to leap and use their claws in conflicts. Chickens are capable of mobbing and killing a weak or inexperienced predator, such as a young fox. Chickens have been thought of primarily as providers of food, but their cognition, emotions, and sociality are comparable with other birds and mammals. A male's crowing is a loud and sometimes shrill call, serving as a territorial signal to other males, and in response to sudden disturbances within their surroundings. Hens cluck loudly after laying an egg and to call their chicks. Chickens give different warning calls to indicate that a predator is approaching from the air or on the ground.

A cockfight is a contest held in a ring called a cockpit between two ♥♥♥♥♥. Cockfighting is outlawed in many countries as involving cruelty to animals. The activity seems to have been practised in the Indus Valley civilisation from 2500 to 2100 BC. In the process of domestication, chickens were apparently kept initially for cockfighting, and only later used for food.

The red junglefowl is well adapted to take advantage of the vast quantities of seed produced during the end of the multi-decade bamboo seeding cycle, to boost its own reproduction. In domesticating the chicken, humans took advantage of the red junglefowl's ability to reproduce prolifically when exposed to a surge in its food supply.
Exactly when and where the chicken was domesticated was controversial. Genomic studies estimated that the chicken was domesticated 8,000 years ago in Southeast Asia and spread to China and India 2,000 to 3,000 years later. Archaeological evidence appeared to support domestic chickens in Southeast Asia well before 6000 BC, China by 6000 BC and India by 2000 BC. An early study proposed that a single domestication event of the red junglefowl in present-day Thailand gave rise to the modern chicken. A 2020 Nature study that fully sequenced 863 chickens across the world suggests that all domestic chickens originate from a single domestication event of red junglefowl (Gallus gallus) whose present-day distribution is predominantly in Southeast Asia. These domesticated chickens spread across Southeast and South Asia where they interbred with local wild species of junglefowl, forming genetically and geographically distinct groups. Analysis of the most popular commercial breed shows that the White Leghorn breed possesses a mosaic of divergent ancestries inherited from different subspecies of red junglefowl.
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. The paleo-anatomist Joris Peters and the bioarchaeologist Greger Larson state that this coincided with the growing of rice, and propose that wild jungle fowl were attracted to eat the rice seeds, nested nearby, and became domesticated. Skeletons of birds in the Gallus genus were used as grave goods at the site, confirming domestication.

A word for the domestic chicken (*manuk) is part of the reconstructed Proto-Austronesian language, indicating they were domesticated by the Austronesian peoples since ancient times. Chickens, together with dogs and pigs, were carried throughout the entire range of the prehistoric Austronesian maritime migrations to Island Southeast Asia, Micronesia, Island Melanesia, Polynesia, and Madagascar, starting from at least 3000 BC from Taiwan. These chickens may have been introduced during pre-Columbian times to South America via Polynesian seafarers, but this is disputed.
Africa:
Chickens reached Egypt via the Middle East for purposes of cockfighting about 1400 BC and became widely bred in Egypt around 300 BC. Three possible routes of introduction into Africa around the early first millennium AD could have been through the Egyptian Nile Valley, the East Africa Roman-Greek or Indian trade, or from Carthage and the Berbers, across the Sahara. The earliest known remains are from Mali, Nubia, East Coast, and South Africa and date back to the middle of the first millennium AD.
Americas:
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. A lack of data from Thailand, Russia, the Indian subcontinent, Southeast Asia and Sub-Saharan Africa makes it difficult to lay out a clear map of the spread of chickens in these areas; better description and genetic analysis of local breeds threatened by extinction may also help with research into this area. Chicken bones from the Arauco Peninsula in south-central Chile were radiocarbon dated as pre-Columbian, and DNA analysis suggested they were related to prehistoric populations in Polynesia. However, further study of the same bones cast doubt on the findings.
Eurasia:
Chicken remains have been difficult to date, given the small and fragile bird bones; this may account for discrepancies in dates given by different sources. Archaeological evidence is supplemented by mentions in historical texts from the last few centuries BC, and by depictions in prehistoric artworks, such as across Central Asia. Chickens were widespread throughout southern Central Asia by the 4th century BC.
Middle Eastern chicken remains go back to a little earlier than 2000 BC in Syria. Phoenicians spread chickens along the Mediterranean coasts as far as Iberia. During the Hellenistic period (4th–2nd centuries BC), in the southern Levant, chickens began to be widely domesticated for food.
The first pictures of chickens in Europe are found on Corinthian pottery of the 7th century BC.
Breeding increased under the Roman Empire and reduced in the Middle Ages. 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.

Chickens are featured widely in folklore, religion, literature, and popular culture. The chicken is a sacred animal in many cultures and deeply embedded in belief systems and religious practices. Roosters are sometimes used for divination, a practice called alectryomancy. This involves the sacrifice of a sacred rooster, often during a ritual cockfight, used as a form of communication with the gods. In Gabriel García Márquez's Nobel Prize-winning 1967 novel One Hundred Years of Solitude, cockfighting is outlawed in the town of Macondo after the patriarch of the Buendia family murders his cockfighting rival and is haunted by the man's ghost. The pseudo-riddle "Why did the chicken cross the road?" dates to 1847, or earlier. Chickens have been featured in art in farmyard scenes such as Adriaen van Utrecht's 1646 Turkeys and Chickens and Walter Osborne's 1885 Feeding the Chickens. The nursery rhyme "♥♥♥♥ a Doodle Doo", its chorus line imitating the cockerel's call, was published in Mother Goose's Melody in 1765. The 2000 animated adventure comedy film Chicken Run, directed by Peter Lord and Nick Park, featured anthropomorphic chickens with many chicken jokes.

⠂⠚⠋⠉⢠⣉⡱⣶⣤⣠⣦⣹⣿⣿⣿⣿⣿⣶⣄⣀⡀⠀⣤⣶⣊⣉⡉⠋⠀⠀
⣴⣶⣶⣶⣶⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣷
⠿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⡿⠟⢉
⣀⡀⠙⠻⠿⢿⣿⡿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⡿⠿⠋⠉⣀⣀⡠⠞⠋
⠉⢻⣷⣶⣤⣀⡀⠈⠀⠉⠉⠙⠻⠿⣿⣿⣿⡿⠟⠋⠉⢀⣴⣶⣿⠟⠉⠀⠀⠀
⠀⠀⠈⠛⢿⣿⣿⣿⣷⣦⣤⣄⡀⠀⠀⠀⠀⠀⣠⣴⣾⣿⡿⠋⠁⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠙⠻⢿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⡿⠋⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠛⠏⠙⠿⠿⣿⣿⣿⣿⠿⠿⠋⠀⠀⠀⠀ Never forget, Annoying Crow lives on...