Well, you can't blame the chickens. They started out flying, after all. At least their ancestors did. Their beaks are better adapted to pecking off the ground, their feet to walking instead of perching, and their wings are smaller than other birds their size.
Chickens comprise some of the thousands of artificial breeds that humans have created.
Many domestic fowl, turkeys especially, have such large, um, breast portions, that they can no longer breed normally and must be artificially inseminated. This is a double whammy to the male poultry ego, such as it is. And if you can tell your buddies that at happy hour, maybe they'll let you drive. Cecil's Mailbag is researched and written by members of the Straight Dope Science Advisory Board, Cecil's online auxiliary. Inc. All rights reserved.