Years of building, then burning giant, flammable wooden chickens gets one to wondering about the magical multiformity of the world’s most popular poultry. Farms and fields around the globe boast a veritable cornucopia of chickens. The Single-Comb White Leghorn is the species that usually comes to mind when one thinks of chickens; such is the enduring legacy of the great entertainer, Foghorn Leghorn. But hundreds of other distinct breeds, from Altsteirers to Zottegems campine, populate farmyards around the world. Chickens can be white, black, brown, red, gray, speckled, or barred. They can have cochins (fluffy feet), houdins (top knots), silkies (long silky coats), or frizzles (curly feathers). There are seven distinctive types of combs alone on chickens — rose, strawberry, single, cushion, buttercup, pea, and V-shaped, in case you were wondering. Hundreds of different birds of various sizes and colors, and yet not a one appears on the official ABA Checklist. How can this be?
Domesticated chickens have not always existed in such variety. In 1868, Charles Darwin published a census of all of the chicken breeds existing at the time, one of his less impressive feats considering there were only thirteen of them. There are plenty more now yet, in spite of this marked diversity, all domesticated chickens belong to the same species, the aptly named Domestic Chicken (Gallus domesticus). Birders show little interest in this species, since it has no place on an official bird list. If you’re wondering why, the word “domestic” should be a decent clue.
Domestic animals do not just spring into existence, no matter what the creationists say. We may not know whether the chicken or the egg came first, but identifying which chicken came first is child’s play. The primogenitor of countless domesticated breeds is the Red Junglefowl (Gallus gallus) of southern Asia. This mighty bird, truly the chicken of chickens, is brilliantly colored with feathers of red, green, brown, black, and gold. Ironically, although its sons and daughters now outnumber human beings, the true Red Junglefowl is now endangered. Very few flocks of genetically pure wild stock are known to exist. These birds are identified by morphological indicators such as the absence of a comb in females, horizontal tail carriage in both sexes, dark or slate gray leg color, and an annual molt and eclipse plumage in males. It is estimated that 99% of all Red Junglefowl have crossbred with domestic birds.
In deference, no doubt, to its extreme commonness and uncommon deliciousness (if your tastes run in that direction), the chicken received a singular honor. In March 2004, the National Human Genome Research Institute announced that the first draft of the chicken genome sequence had been made public for use by biomedical and agricultural researchers around the world. A team led by Richard Wilson, Ph.D., from the Washington University School of Medicine in St. Louis successfully assembled the genome of the Red Junglefowl. Comprised of about 1 billion DNA base pairs, the chicken genome is the first avian genome to be sequenced. This development not only has implications for the treatment of hazards like avian influenza, it may presage breakthroughs in human biology.
So let us praise the chicken. First domesticated around 2500 B.C., this noble fowl has spread across the globe to provide humans with entertainment (chickens were first bred for cockfighting, not eating), nutrition, and inspiration. A primitive creature with advanced breeding, the chicken has been our captive and companion in civilization. One researcher estimated that chickens moved from Asia to Europe over several centuries at the rate of 1.5 to 3 kilometers per year, consistent with rates of other trappings of society like technologies and ideas. With us through thick and thin, this fowl is no fair-weather friend. Thank a chicken today.