Allantois breaks through amnion. Day 5 Proventriculus and gizzard formed. Formation of reproductive organs and sex determined. Day 6 Formation of beak and egg-tooth begins. Main division of legs and wings.
Voluntary movement begins.
Day 7 Indications of digits in legs and wings are visible. Abdomen more prominent due to development of viscera. Day 8 Formation of feathers begins. Day 9 Embryo begins to look bird-like. Mouth opening appears.