[paul.fr]

I know they hatch, but is hatching the same as birth? Afterall, they are alive, concious ...before they hatch.

[rosalind dna]

yes the baby birds hatch out the eggs by poking their tiny heads out into the world but the albument and yolk in the egg(s) give
the baby birds nutrition.

[blakestyger]

Being hatched is the same as being born - it's just the emergence of the fully developed embryo from the egg (which could be seen as an analogue of a womb).
The difference with birds is that some are able to potter about, feed and run etc immediately (precocial) whilst others are helpless and need rearing in the nest for a while (altricial).

[Madidus_Scientia]

does oxygen diffuse through the shell? or do they just have enough in there to last them until they hatch?

[rosalind dna]

The eggshells are porous so that is how the baby birds can breathe but not enough to drown when it rains or suffocate when a parent bird nests the egg(s).