Day 10: The nostrils are present as narrow apertures. Growth of eyelids. Extension of the distal portion of the limbs. The vitelline membrane completely surrounds the yolk. Feather follicles now cover the inferior part of the limbs. Appearance of the egg-tooth.
Day 11: The palpebral aperture has an elliptic shape that tends to become thinner. The allantois reaches its maximum size while the vitellus begins to shrink. The embryo now has the aspect of a chick.