Where in the oviduct is the chalazae formed and wrapped around the yolk?

The chalazae are two helical bands of strong, fibrous protein (mucin) that extend from opposite poles of the yolk to the outer membranes, holding the yolk in the exact center of the albumen. The physical formation and wrapping of these structures begin as the ovum (yolk) exits the infundibulum and enters the proximal section of the magnum (the albumen-secreting region of the oviduct). Here, dense layers of inner thick albumen are secreted directly onto the vitelline membrane of the yolk. As the egg travels down the oviduct, it undergoes a slow, continuous spiral rotation driven by the longitudinal muscle fibers in the walls of the magnum. This rotational movement twists the mucin fibers at the anterior and posterior ends of the egg, spinning them into tight, elastic ropes (the chalazae). This mechanical positioning is vital for embryonic survival, preventing the yolk from rising and sticking to the shell. Breeders can study embryology in the Poultry Encyclopedia, buy premium breeder feeds on Poultry Plaza, track chick rates on Poultry Rates, and list high-fertility hatching eggs on Murghi Mandi.