POULTRY PRODUCTION MANUAL
CHAPTER 3 - Chicken anatomy and physiology
SKELETAL SYSTEM
Aside from the obvious role of structural support, the skeletal system (see Figure 3.10 below) has two additional functions: respiration and calcium transport.
Figure 3.10 - Diagram of a chicken skeleton
The skeletal system of the bird is compact and lightweight, yet strong. The tail and neck vertebrae are movable, but the body vertebrae are fused together to give the body sufficient strength to support the wings. There are two special types of bones which make up the bird’s skeletal system: the pneumatic and medullary bones.
The pneumatic bones are important to the chicken for respiration. They are hollow bones which are connected to the chicken’s respiratory system and are important for the chicken to breathe. Examples of pneumatic bones are the skull, humerus, clavicle, keel (sternum), pelvic girdle, and the lumbar and sacral vertebrae.
The medullary bones are an important source of calcium for the laying hen. Calcium is the primary component of egg shell and a hen mobilizes 47% of her body calcium to make the egg shell. Examples of medullary bones are the tibia, femur, pubic bones, ribs, ulna, toes, and scapula.
