The empty part photographed is where the allantois and valve are located.

Egg illumination refers to using an egg illumination lamp to see through the eggs under dark conditions after incubation for a certain period of time to check the development of the chicken embryos and remove unfertilized eggs and early dead embryonic eggs. Taking care of eggs is an indispensable part of the egg hatching process.

The first egg care is carried out on the 8th day after hatching. Through the egg care, infertile eggs and dead embryonated eggs are picked out. The embryo of the fertilized egg develops normally, with blood vessels distributed radially and brightly red in color; the dead embryonated egg is lighter in color, with irregular blood arcs and blood rings, and no radial blood vessels; the infertile egg is bright and has no vascular network, and can only See the shadow of the yolk.