with age. Chickens have stronger legs and are regularly grasped by their legs when picked up.

The feet of each group is unique. The waterfowl are adapted for quickly moving on the surface of the water, and their feet are webbed to allow for this kind of locomotion. Birds that spend long periods standing on ice or cool ground have adapted specialized thermoregulation in their webbed feet. A countercurrent heat exchange system consisting of the warm blood traveling