The history of chickens (Gallus domesticus) is a bit of a puzzle. They were first domesticated from a wild form called red junglefowl (Gallus gallus), a bird that still runs wild in most of southeast Asia. That occurred probably about 8,000 years ago in what is now Thailand; however, recent research suggests there may have been multiple origins in distinct areas of South and Southeast Asia.
Wild Chickens: The Red Junglefowl
Since the wild progenitor of chickens is still among us, comparisons of behavior and other changes that exist are available to us. Behaviorally, domesticated chickens are less active, have fewer social interactions, are less aggressive to would-be predators, and are less likely to go looking for foreign food sources than their wild ancestors. Other changes include increased adult body weight and simplified plumage; egg production starts earlier, is more frequent, and produces larger eggs.
Genetic studies suggest that the original domesticated chicken was probably in Thailand, although multiple origin locations have been suggested as well. The first archaeological evidence to date is from China about 5400 BC, in geographically widespread sites such as Cishan (Heibei province, ca 5300 BC), Beixin (Shandong province, ca 5000 BC), and Xian (Shaanxi province, ca 4300 BC). Domesticated chickens appear at Mohenjo-Daro in the Indus Valley by about 2000 BC and, from there the chicken spread into Europe and Africa.
History of Chickens in the Americas
It is believed that chickens were brought to the Polynesian islands from southeast Asia with the Lapita expansion, about 3300 years ago. While it was assumed that they had been brought to the Americas with the Spanish conquistadors, in fact pre-Columbian chicken has been identified at several sites throughout the Americas, most notably at the site of El Arenal-1 in Chile, ca 1350 AD.
However, in 2008, a paper in PNAS by Gongora et al. contradicts the findings of Storey et al. Read about it here: Chickens and Trans-Pacific Crossings, Part 2
Sources
This article is part of the About.com Guide to the History of Animal Domestication.
Gongora, Jaime, et al. 2008 Indo-European and Asian origins for Chilean and Pacific chickens revealed by mtDNA. Proceedings of the National Academy of Sciences 105(30):10308-10313.
Jensen, Per. 2006. Domestication--From behavior to genes and back again. Applied Animal Science 97:3-15.
Liu, Yi-Ping et al. 2006. Multiple maternal origins of chickens: Out of the Asian jungles. Molecular Phylogenetics and Evolution 38: 12–19
Storey, Alice A., et al. 2007 Radiocarbon and DNA evidence for a pre-Columbian introduction of Polynesian chickens to Chile. Proceedings of the National Academy of Sciences 104(25):10335-10339.
West, Barbara and Ben-Xiong Zhou. 1988. Did chickens go north? New evidence for domestication. Journal of Archaeological Science 15:515-533.
This glossary entry is part of the Dictionary of Archaeology. Any mistakes are the responsibility of Kris Hirst.
