It is largely clear when cattle, sheep or pigs were domesticated. When it comes to chickens, however, this question has been a source of controversy among experts for years – probably also because the bones don’t last long and because the domestic chicken (Gallus gallus domesticus) was used for various purposes: for ritual reasons, for entertainment, for meat and also for Supply of eggs.
According to one study, the keeping of chickens as reliable suppliers of eggs goes back at least 2,400 years. This is what a research group led by archaeologist Carli Peters from the Max Planck Institute for Geoanthropology in Jena concludes from the analysis of twelve archaeological sites in Central Asia. This use spread rapidly along the Silk Road to the Eastern Mediterranean and then to Europe, the group writes in the specialist journal Nature Communications.
When and where the domestic chicken was domesticated is controversial. This is also because bird bones and egg shell fragments were often mistakenly attributed to chickens, even though they came from other animals, the group writes. Many dates also turned out to be unreliable or incorrect. It is generally agreed that the domestic chicken is descended from the Bankiva chicken (Gallus gallus), which is native to South Asia and whose habitat extended from Thailand to India. The domestic chicken may also go back to another representative of the crested chickens (Gallus).
The oldest chickens kept to lay eggs lived in the region of what is now Uzbekistan
Peters’ group now examined a dozen sites in Central Asia along the Silk Road. The oldest evidence of chickens providing eggs comes from Bash Tepa near the city of Bukhara in Uzbekistan and dates back to around 400 BC. The shell fragments were clearly identified as domestic chicken eggs based on residues of typical proteins. And the study concludes from the sheer number of shell fragments that these chickens did not just lay eggs seasonally. It is unclear over what periods of the year and how many eggs these early domestic chickens produced. But: These quantities cannot be traced back to the wild precursors, which only laid up to six eggs once a year. “This is the earliest evidence of the loss of seasonal egg-laying found in archaeological records to date,” study leader Robert Spengler is quoted as saying in a statement from the institute.
At all archaeological sites examined in the study from the fourth century BC onwards, the team found large quantities of chicken egg shell fragments. The researchers found none of this at older archaeological sites. The group concludes that chickens with the ability to lay eggs for long periods of time spread rapidly along the Silk Road.
In general, however, the question of the origin and distribution of domestic chickens is one of the most puzzling when it comes to domesticated animals, the group complains. Cattle, goats and sheep were domesticated around 10,000 years ago. According to some studies, this step occurred in chickens more than 9,000 years ago, either in Burma, India, Thailand or China. Other studies assume that the animals were only domesticated in Thailand around 3,500 years ago. According to some theories, chickens were initially kept for ritual purposes or competitions. There are detailed images of roosters in battle on Greek ceramics from around 620 BC.