Many traits associated with domestication are suggested to have developed as correlated responses to reduced fear of humans. Tameness may have reduced the stress of living in human proximity and improved welfare in captivity. We selected Red Junglefowl (ancestors of all domestic chickens) for four generations on high or low fear towards humans, mimicking an important aspect of the earliest period of domestication, and tested birds from the third and fourth generation in three different social tests. Growth and plumage condition, as well as size of eggs and offspring were also recorded, as indicators of some aspects of welfare. Birds selected for low fear had higher weight, laid larger eggs and generated larger offspring, and had a better plumage condition. In a social dominance test they also performed more aggressive behaviour and received less of the same, regardless of whether the restricted resource was feed or not. Hence, dominance appeared to increase as a consequence of reduced fear of humans. Furthermore, egg size and the weight of the offspring were larger in the less fearful birds, and plumage condition better, which could be interpreted as the less fearful animals being better adapted to the environment in which they were selected.

Using archaeological evidence for chicken domestication from China, Asia and Europe, as well as palaeoclimatic evidence from China, it is concluded that chickens were first domesticated from the red junglefowl Gallus gallus in Southeast Asia well before the sixth millennium BC and taken north to become established in China by c. 6000 BC, whence they were later introduced to Japan via Korea during the Yayoi Period (c. 300 BC-300 AD). Domestication occurred in India much later (c. 2000 BC?), either independently or as a diffusion from Southeast Asia. Although the Iron Age was the main period for dispersion of chickens throughout Europe, they were already present in some areas during the late Neolithic and early Bronze Age. It is proposed that the earliest European material may be derived from China via Russia. Because the key is likely to lie in central areas of the USSR, the finding of positive or negative evidence for the theory will depend on the interest of archaeologists working in the Soviet Union. Their collaboration is invited.