There are three types of muscles in the chicken’s body: smooth, cardiac, and skeletal.
Smooth muscle is controlled by the autonomic nervous system (ANS) and is found in
the blood vessels, gizzard, intestines and organs. The cardiac muscle is the specialized
muscle of the heart. The skeletal muscle is the type of muscle responsible for the
shape of the bird and for its voluntary movement. This is the muscle type that makes up
the edible portions of the carcass. The most valuable skeletal muscles in a poultry
carcass are the breast, thigh and leg.