It's a sack and not an egg but the primary food source, the only one, is the placenta and the nutrients go via the umbilical cord.
In birds and reptiles only .
An egg.
Initial development of the egg, including the embryo, begins inside the mother bird after she mates with a male. The embryo, yolk, and shell initially form together. After the egg is laid the bird embryo continues to grow, drawing the nutrients it needs from the yolk.
The same way as a birds egg - with a yolk sac. The embryo feeds off the yolk-sac while it's developing inside the egg.
Bird eggs are adapted to land by having a hard outer shell that protects the growing embryo from damage and dehydration. The shape of the egg also helps prevent it from rolling away and provides structural support for the developing bird. Additionally, the eggs have a membrane inside the shell that allows for gas exchange to occur while protecting the embryo.
Babe, or a young animal, forms through the process of reproduction. In mammals, this typically involves fertilization of an egg by sperm, leading to the development of an embryo within the mother's womb. The embryo undergoes various stages of development, eventually growing into a fully formed young animal, which is born when the gestation period is complete. In other species, such as birds or reptiles, eggs are laid and the young develop inside the egg before hatching.
No, That means it is infected with bacteria and is about to explode. If you had candled them earlier you would have noticed there wasn't an embryo growing inside and could have discarded it then. The best thing to do is to carefully cover it with a damp washcloth and remove if from the incubatorbecause if it explodes most of the birds that hatch will die.
The embryo that does not have an amnion is the human embryo. It is a membrane that covers the embryo when first formed. Mammals, reptiles and birds have this feature.
They create it as part of their metabolism, the activities of living, growing, and moving.
Mammals, birds, and reptiles all derive from a single common ancestor.
So the embryo can breathe!!
AlexisLawrence Romanoff has written: 'Pathogenesis of the avian embryo' -- subject(s): Abnormalities (Animals), Abnormities and deformities, Birds, Chick Embryo, Embryobiology, Fetus