Virtually no growth. Stage of inactive embryonic life During Incubation Day 1 Development of area pellucida and area opaca of blastoderm.
Blood vessels appear in the yolk sac.
Amnion completely surrounds embryo. Day 4 Formation of tongue begins. Embryo completely separate from yolk sac and turned on left side. Allantois breaks through amnion. Day 5 Proventriculus and gizzard formed.