The chicken has two legs and two wings, a fact that influences housing and management. Domestic chickens have essentially lost the ability to fly. Heavy breeds used for meat production cannot do more than flap their wings and jump to a little higher level or move more rapidly along the ground. The lighter-bodied birds can fly short distances, and some can fly over relatively high fences. The feet and shank portions of the legs have scales.
Respiration rate is higher in chickens than in larger animals.
In general, it can be said that the smaller the kind of bird the faster it breathes. For example, a hummingbird breathes more times a minute than a chicken. The male chicken breathes about 18 to 21 times a minute and the female about 31 to 37 times when they are not under stress. The heart beat of chickens is rather fast, being about 286 times a minute in males and 312 in females in a resting condition. Digestion rate is somewhat rapid in chickens.