There are more chickens than any other bird on earth. There are three chickens for every human being on our planet and they have become indispensable as basic food. But the question of where chickens come from and how people came to keep and eat chickens has eluded us until now. But now we know more.
For many people, it is difficult to see chickens as anything other than food. But two new studies are changing our understanding of the human-chicken relationship.
One of these new studies dated bones from 23 of the earliest chickens in Europe and Northwest Africa to test their age. This gives us a clearer understanding of when they arrived in these areas and how people interacted with them. Only five copies matched the dates that archaeologists had previously assigned them. The other 18 were much newer than previously thought, sometimes thousands of years later.
Previous hypotheses, which based their data on contextual clues, such as where these bones were located and what other artifacts they were found with, suggested that chickens existed in Europe up to 7,000 years ago. But the new results show that they were not introduced until around 800 BC. (2,800 years ago).
This shows that chickens arrived in Europe quite recently compared to domestic cattle, pigs and sheep, which reached our own about 6,000 years ago. The new dating also suggests that in many places there was a delay of several hundred years, from the time the hens were first introduced to an area until they were actually considered food.
In the grave
Many of the early identified chickens are complete or almost complete skeletons. In Britain, none of the oldest skeletons show evidence that they have been slaughtered for human consumption. They were often older animals, buried in pits. One specimen even had a well-healed fracture, suggesting human care. That hen could also still lay eggs: She had a substance called medullary bone in the skeleton, which is formed during egg production.
These clues suggest that rather than being considered a food source, these early arrivals to Northern Europe were more likely to have been considered particularly exotic, especially given their small population size at the time.
In some places, shortly after the chickens were introduced, we find them buried with humans. A new study of late Iron Age British burials and Roman burials with chickens indicates that these burial rites were often gendered: men were buried with roosters and women with chickens. Their role may have been to lead human souls into the afterlife.
Gallus gallus spadiceus
Such a role would have been consistent with their association with Mercury (the Roman god of communication and travel). Large numbers of roosters were sacrificed to Mercury in temples. In other cases, the chickens in the graves were a food offering. This is a practice that became more common in Britain during the Roman period.
Clearly, the relationship between humans and chickens was complex for a while and involved more than just food. So where did these unusual birds first come from?
Recent DNA analyzes confirmed that chickens were domesticated from a subspecies of red jungle chicken called Gallus gallus spadiceus, which lived in South or Southeast Asia. This would mean that chickens were domesticated in this wide region.
So far, there have been three main hypotheses about location and timing. First domestication about 4,000 years ago in the Indus Valley. The other says it happened more than 8,000 years ago in Southeast Asia. The third sees their origins in northern China 10,000 years ago.
However, these theories fail to take into account crucial factors such as dating uncertainty, skeletal similarities between chickens and other local wild species, and the broader cultural and ecological context.
No chickens without rice
Another new study aims to identify the species, tame status and date the oldest reported chicken bones from more than 600 archeological sites in 89 countries on four continents. The researchers found that all three hypotheses are incorrect. The oldest bones, now certainly attributed to domestic chickens, come from the Neolithic site of Ban Non Wat in central Thailand and date to about 3,500 years ago – much later than previously thought.
Although there is still a lack of clarity as to why chickens were domesticated, one thing seems to have brought chickens and humans together: rice. The introduction of dry rice cultivation in central Thailand coincides with the dating of the oldest chicken remains. This suggests that the new type of agriculture may have been a catalyst for the domestication process.
Clearing the jungle for grain cultivation would have created a comfortable environment for the red jungle chicken. At the same time, the newly cultivated rice, along with millet, is said to have brought the wild jungle hens into close contact with humans, which nourished the domestication process, after which their descendants of chickens were scattered around the world by migrating humans.