Ovary A female chick is born with a fully formed ovary containing several thousand tiny ova, or future yolks. Each yolk is enclosed in its own sac or follicle. The follicle contains a highly developed system of blood vessels which carry nourishment to the developing yolk. At ovulation, the follicle ruptures to release the yolk into the oviduct. A double-yolked egg is the result of two yolks being released at the same time.
Rupture occurs at the stigma line , an area of the follicle which has no blood vessels.
The infundibulum , also know as the funnel, captures the ovulated yolk. This is where fertilization, if it occurred, would take place. After about 15 minutes, the yolk passes along to the magnum . Here, in approximately 3 hours, the albumen is deposited around the yolk. As the albumen is formed, the yolk rotates, twisting the albumenous fibers to form the chalazae.