Domestic Chicken

by John Shackford

Thanksgiving is coming and one of the things we have to be thankful for is abundant food. Turkey is the Thanksgiving tradition but the Domestic Chicken (Gallus gallus domesticus) is a less daunting choice. The Domestic Chicken is the most abundant bird species on earth. The number, worldwide, was estimated to be over 24 billion in 2003 and world population at that time was about 6.4 billion. So in 2003 there were about 3.75 chickens for every person on earth. We do not usually stop and think about how Domestic Chickens came to be and this I would like to explore a bit here.

Genetically, chickens are believed to be derived primarily from (wild) Red Junglefowl (Gallus gallus) (see photo), a species that Domestic Chickens strongly resemble and from which most of the traits of Domestic Chickens are no doubt derived. Wild Red Junglefowl still range from southern India eastward across southern China. There are 3 other wild junglefowl: the Grey Junglefowl, found on peninsular India and northward toward the northern boundary; Sri Lankan Junglefowl, found on the island of Sri Lanka, off the coast of India; and the Green Junglefowl, found on the Island of Java and several smaller islands in the area, in Indonesia. All may have contributed to the genetics of Domestic Chickens. The Grey Junglefowl is believed to have contributed the trait of yellow pigment in the feet and legs of Domestic Chickens.

The Red Junglefowl is quite a shy species, unlike its domestic cousins. And what do you think the call of the Red Junglefowl is—yes, Cock-a-doodle-doo. Such a loud call in the jungle suggests a very difficult-to-see/shy bird, because showy birds do not require loud calls to attract a mate. The earliest known domestication of the chicken is estimated to be in Northern China about 8,000 BCE (Before Common Era), an estimated date determined by archaeological discovery of chicken bones in ancient ruins, according to one source. Another reference to earliest domestication is before 7,400 BCE. In any case, it was a long time ago. As a comparison, the Egyptian pyramids in some estimates were built about 4,600 BCE, based on carbon dating, pottery shards and the like. So domestication of the Red Junglefowl apparently predates the building of the pyramids.

I wonder how the Red Junglefowl, a shy species, was “tamed” by ancient people. I put quite a bit of thought into this and finally hit upon something I believe would have been both effective and simple: I think junglefowl chicks, or pipping eggs were found and taken home, where these chicks, after hatching, became imprinted on humans. Then the growing chicks would likely hang around their human “parents” and their “parents” villages. In any case our Domestic Chicken is quite a different bird, behavior wise, than the junglefowl from which they arose. Now all 4 junglefowl are raised in captivity.

And what about Domestic Chickens laying eggs year around? Up until modern times chickens laid eggs mainly in the springtime, when there was the proper amount of sunlight and moderate temperatures. Springtime laying of eggs is a good part of where the tradition of Easter eggs comes from. In modern times, chickens have been induced to lay eggs year round by keeping them indoors and controlling the light and temperature. But apparently this is not all there is to this story because now many chickens that are not kept indoors still lay eggs all year round. Once when I was about 12 years old, I had a bantam hen and my younger brother Hilliard had one too. We were moving about a hundred miles to a new home, and the bantams were both closed up in the same box in the car. When we arrived at our destination and opened the box, along with the two hens there was an egg that one of them had laid. My brother and I began quibbling over whose chicken laid the egg. My brother claimed that it was his egg because his chicken always crowed when it laid an egg, though I am not even sure his chicken had ever made such a noise. We still argue over whose egg that was!