The muscular system of a chicken comprises of around three-quarters of its body weight. Chickens, like every animal, have three muscle types: skeletal muscles, cardiac muscles and smooth muscles.
The skeletal muscle, more commonly known as the striated muscle, is the muscle responsible for forming the shape of the chicken and forming its voluntary movements. The cardiac muscle is a specialized muscle associated with the heart. The smooth muscle is controlled by the chicken’s autonomic nervous system and is located in the organs, intestines, gizzard and blood vessels. These muscles are attached to the bones by fibrous, tough strands known as tendons.