Researchers Pinpoint Date When Chickens Were First Domesticated

Scientists have debated where domestic chickens originated from for decades. Southeast Asia, India, and northern China have all been proposed places of origin, with the chicken’s first appearance ranging between 4,000 to 10,500 years ago.

Now, researchers have more precisely pinpointed the origins of domesticated chickens in two new studies. The first, published this month in the Proceedings of the National Academy of Sciences (PNAS), found that the chicken’s domestication began in rice fields planted by Southeast Asian farmers 3,500 years ago, reports Bruce Bower for Science News. Soon after, the birds were moved westward, where they were treated as exotic and culturally revered animals and not as a source of food. The second study, published in Antiquity, found that the domesticated fowl arrived in Mediterranean Europe around 2,800 years ago and then appeared in Africa 1,100 and 800 years ago.  

In 2020, a study confirmed that the living chicken’s ancestor was the jungle fowl subspecies, Gallus gallus spaedicus, narrowing the area of domestication to Southeast Asia. The PNAS study findings were even more specific, and showed that after humans planted rice within the range of the red jungle fowl (Gallus gallus), a tropical bird in the pheasant family. Biologist Charles Darwin first proposed that chickens may have descended from the red jungle fowl because of their similar appearances, per Science.

Living chickens couldn’t be used to narrow down the time window for domestication, because doing so requires a type of paleontology based on DNA sequencing, and the genes that researchers have used to date modern chickens only appeared in domesticated chickens in the last millennia or so. So, researchers turned to reevaluate the dates and records of chicken bones from 600 archeological sites worldwide, Science reports. The earliest chicken remains came from Ban Non Wat, in Central Thailand, a dry rice farming site known to be inhabited since the Neolithic Age. The earliest chicken remains came from between 1650 B.C.E. and 1250 B.C.E., during the Bronze Age. Instead of being flooded like paddies, the fields were soaked by seasonal rains and attracted hungry wildfowl. The researchers note that this led to chicken domestication around 3,500 years ago, Science News reports. Experts also found a correlation between the spread of dry rice farming, millet and other grains with the spread of chicken bone trails across Asia, the Middle East and Africa, Science reports.

“This created a more open, less [tree-covered] environment, which is actually an environment where red junglefowl thrive,” Ophélie Lebrasseur, an archeologist and co-author of the first study, says to New Scientist. “And they could have fed on the waste from human societies.”

In the second study published in Antiquity, radiocarbon dating found that 23 chicken bones from 16 sites in Eurasia and Africa were younger by thousands of years than previously thought. The bones were incorrectly dated based on the depth of the sediment they were found in, because they settled into lower sediment layers over time and were found with other items made by earlier humans, Science News reports. Chicken remains found in an Etruscan site were dated to 2800 years ago and may be when chickens first entered Europe, Science reports.

Archeologists have found people being buried with the remnants of chickens, rather than discarded as scraps, making a domestic relationship clear, reports New Scientist’s Colin Barras. Because the birds were buried with humans, it suggested that they had a cultural or social significance and were sacred creatures instead of a food source, which means that a desire for meat did not drive the domestication of the chicken.

Elizabeth Gamillo | | READ MORE

Elizabeth Gamillo is a correspondent for Smithsonian and a science journalist based in Milwaukee, Wisconsin. She has written for Science magazine as their 2018 AAAS Diverse Voices in Science Journalism Intern.