I know fishes, birds, lizards, etc. lay and hatch from eggs (mostly), but apparently, they can also be born (out of eggs):
Birds born in a cage think flying is an illness.
There are also such statements as:
No bird gives birth to live young.
Some birds are known to give live birth.
They sound like most/all birds give some kind of birth other than live birth to young, though I'm pretty sure it's not stillbirth or "dead birth".
But some owners of pets celebrate the hatchday instead of birthday. So, apparently, for them, their pets' lives begin with hatch, not birth.
Technically speaking, oviparous animals produce young by means of eggs. But I'm not sure if "this hen produced the chicks", for example, is idiomatic in everyday conversation.
So would you say "this hen gave birth to the chicks"?