The annals of Ancient Egyptian king Thutmose III described a marvelous foreign bird that “gives birth daily.” Zoroastrians viewed them as spirits whose cries told of the cosmic struggle between darkness and light. Romans brought them on their military campaigns to foretell the success of future battles. And today, this bird still occupies an important, though much less honorable position – on our dinner plates.
The modern chicken is descended primarily from the Red Junglefowl, and partially from three other closely related species, all native to India and Southeast Asia. The region’s bamboo plants produce massive amounts of fruit just once every few decades. Junglefowls’ ability to lay eggs daily may have evolved to take advantage of these rare feasts, increasing their population when food was abundant. This was something humans could exploit on a consistent basis, and the birds’ weak flight capabilities and limited need for space made them easy to capture and contain.
The earliest domesticated chickens, dating at least back to 7,000 years ago, weren’t bred for food, but for something considered less savory today. The aggressiveness of breeding males, armed with natural leg spurs, made cockfighting a popular entertainment.
By the second millennium BCE, chickens had spread from the Indus Valley to China and the Middle East to occupy royal menageries and to be used in religious rituals. But it was in Egypt where the next chapter in the bird’s history began.
When a hen naturally incubates eggs, she will stop laying new ones and sit on a “clutch” of 6 or more eggs for 21 days. By the middle of the 1st millennium BCE, the Egyptians had learned to artificially incubate chicken eggs by placing them in baskets over hot ashes. That freed up hens to continue laying daily, and what had been a royal delicacy or religious offering became a common meal. Around the same time as Egyptians were incubating eggs, Phoenician merchants introduced chickens to Europe, where they quickly became an essential part of European livestock.
However, for a long time, the chicken’s revered status continued to exist alongside its culinary one. The Ancient Greeks used fighting roosters as inspirational examples for young soldiers. The Romans consulted chickens as oracles. And as late as the 7th Century, the chicken was considered a symbol for Christianity.
Over the next few centuries, chickens accompanied humans wherever they went, spreading throughout the world through trade, conquest, and colonization. After the Opium Wars, Chinese breeds were brought to England and crossed with local chickens. This gave rise to a phenomenon called “Hen Fever” or “The Fancy”, with farmers all over Europe striving to breed new varieties with particular combinations of traits. This trend also caught the attention of a certain Charles Darwin, who wondered if a similar selective breeding process occurred in nature. Darwin would observe hundreds of chickens while finalizing his historic work introducing the theory of Evolution.
But the chicken’s greatest contribution to science was yet to come. In the early 20th century, a trio of British scientists conducted extensive crossbreeding of chickens, building on Gregor Mendel’s studies of genetic inheritance. With their high genetic diversity, many distinct traits, and only 7 months between generations, chickens were the perfect subject. This work resulted in the famous Punnett Square, used to show the genotypes that would result from breeding a given pairing.
Since then, numerous breeding initiatives have made chickens bigger and meatier, and allowed them to lay more eggs than ever. Meanwhile, chicken production has shifted to an industrial, factory-like model, with birds raised in spaces with a footprint no larger than a sheet of paper. And while there’s been a shift towards free-range farming due to animal rights and environmental concerns, most of the world’s more than 22 billion chickens today are factory farmed.
From gladiators and gifts to the gods, to traveling companions and research subjects, chickens have played many roles over the centuries. And though they may not have come before the proverbial egg, chickens’ fascinating history tells us a great deal about our own.
