Research unveils the key moment that transformed chickens into the economically relevant animals that they are today

Chickens, integral to the world's economy today, stand as one of the most consequential animals globally. Their significance spans various industries, from agriculture to gastronomy, solidifying their role in the economic landscape.

The journey of chickens, from their origins to their widespread distribution across the ancient world, remains a subject of intrigue and uncertainty. Recent archaeological advancements have challenged previous understandings, revealing that many bone findings once presumed to be early chickens actually belonged to wild birds.

However, a recent study conducted by an international team of archaeologists, historians and biomolecular scientists has provided groundbreaking insights into the earliest evidence of chicken domestication for egg production. This discovery sheds light on a crucial aspect of ancient human-animal relationships, potentially revealing the primary factors driving the spread of domestic chickens across Eurasia and northeast Africa.
From Silk Road to supermarkets: Investigating the origins of chicken domestication
The research team embarked on a comprehensive investigation, collecting tens of thousands of eggshell fragments from 12 archaeological sites situated along the Silk Road's central corridor in Asia.

Employing advanced biomolecular analysis techniques such as ZooMS, the researchers were able to identify the origins of these eggshells. Unlike traditional genetic analysis, ZooMS relies on protein signals rather than DNA, offering a faster and more cost-effective method for species identification.

Analysing eggshell fragments spanning approximately 1,500 years, the researchers discovered widespread evidence of chicken husbandry in Central Asia between 400 BCE and 1000 CE. This suggests a significant role for this region in the early domestication and dispersal of chickens along the ancient Silk Road.

The identification of these eggshell fragments as originating from domesticated chickens, coupled with their prevalence across various sediment layers at each excavation site, led the researchers to a significant conclusion. It became apparent that domestic chickens were laying eggs out of season, exhibiting a higher frequency compared to their wild ancestor called the red jungle fowl, which nests only once per year and typically lays six eggs per clutch.

“This is the earliest evidence for the loss of seasonal egg laying yet identified in the archaeological record. This is an important clue for better understanding the mutualistic relationships between humans and animals that resulted in domestication,” said Dr. Robert Spengler, leader of the Domestication and Anthropogenic Evolution research group and principal investigator on the study.

All in all, this enhanced reproductive capacity is why domestic chickens became highly desirable to ancient societies, ultimately shaping their evolution into the globally significant species we recognise today.

These findings were published in the journal Nature Communications and can be accessed $4.