Scientists on Monday released new evidence that traces the earliest domestication of chickens to Southeast Asia around 3,500 years ago, refuting longstanding suggestions that domestic chickens had originated in south India or northern China much earlier.

Two studies by international teams of scientists have provided insights into the timing and circumstances of the domestication of chickens from wild jungle fowl in Southeast Asia before they spread into India and West Asia, reaching Europe only by 800 BC.

The studies, of ancient bird bones from over 600 sites in 89 countries, have brought forward the antiquity of chickens and shown that poultry farming in South Asia was a post-Harappan development.

They also suggest that the arrival of rice farming may have been a driving force behind chicken domestication. The paddy fields may have attracted wild jungle fowl down from the trees, kick-starting a relationship between them and people, leading to the emergence of chickens.

The scientists have identified bones, dated between 1,650 BC and 1,250 BC, from a site called Ban Non Wat in central Thailand as the oldest bones of a domestic chicken.

“Given how ubiquitous and popular chickens are today, it is startling to see that the earliest confirmed domestic chicken bones date back to only 3,500 years ago,” Ophelie Lebrasseur, a team member and zoo-archaeologist at the University of Toulouse, France, told The Telegraph.

The studies, published on Monday in two research journals — Antiquity and the Proceedings of the National Academy of Sciences — have demonstrated how wrong some previous suggestions were.

The findings are based on an examination of bones, burial locations, historical records and archaeological data from sites across Asia, Europe, Africa and Oceania.

“In many places across Europe and elsewhere, prehistoric chicken bone specimens are much more recent than had been claimed or presumed,” Julia Best, a bio-archaeologist at Cardiff University in the UK and a team member, told this newspaper.

Several earlier scholars had proposed that the Indus Valley civilisation had domesticated chickens between 4,600 and 3,900 years ago, based on two bones from Harappa and four from Mohenjodaro.

But the new analysis indicates that the bone specimens from Harappa and Mohenjodaro had “either been misidentified or are too large to be confidently categorised as prehistoric domestic birds”, Best and her colleagues said in one of the studies.

Chicken bones become prominent across India around 1,200 BC, the researchers said. For instance, they have turned up at several sites – Daimabad, Garhi, Inamgaon, Nevasa, Tuljapur -- associated with the so-called Jorwe culture in Maharashtra, dated between 1,400 BC and 700 BC.

Other scholars had suggested that chickens were domesticated in northern China 8,000 to 11,000 years ago and later moved westwards to Europe. But the latest research indicates that the earliest remains that can be confidently identified as chicken in China are 3,350 years old.

The new findings also suggest that Greek, Etruscan or Phoenician maritime traders had ferried chickens across the Mediterranean into Europe, where they arrived by 800 BC. But the earliest chickens were likely venerated as exotic birds and not viewed as food.

Archaeological excavations have revealed un-butchered chickens buried with people. The new dating work shows a time lag of several hundred years from chickens’ domestication to their being considered as food. For instance, in Britain chickens were not regularly eaten even around AD 200.

“Eating chicken is so common that people think we have never not eaten them,” Naomi Sykes, a team member and zoo-archaeologist at the University Exeter in the UK, said.

“Our evidence shows that our past relationship with chickens was far more complex and that chickens were venerated for centuries.”

Best, who led one of the studies that involved radiocarbon dating of bone specimens from across Europe, said many samples had to be assigned younger dates.

For instance, a chicken bone specimen from Bulgaria had been presumed to be around 7,000 years old, based on the archaeological layers or the cultural artefacts alongside which the specimen had been discovered. “But radiocarbon dating showed that it was less than 100 years old,” Best said.

Among the 23 specimens radiocarbon-dated in Europe and northwest Africa, 18 were younger than the ages they had been assigned on the basis of excavations.

“This underlines the importance of directly dating the bones, and not just depending on the cultural or stratigraphic archaeological associations,” Best said.