"a iesi din ou"
https://dexonline.ro/definitie/ecloziuneRegardless of which animal this is form, it is the product of this action..
The word itself does not EXCLUSIVELY or specifically suggest the "birth" of simply one type of bug, or a bird, or a fish. The actual word is very generic and covers all creatures that "hatch" . I think this is a very genetic word relating to :
"eclozare". But not only concerning chickens.
https://dexonline.ro/definitie/eclozareor hatch: "a scoate" from the egg?
This is to say that you need the NOUN that relates to the product of this family of word, i.e. the word describing the product of "ECLOZIUNE"? or to "A SCOATE" from the egg? I don't know myself, (you will probably know) but I feel this is the direction to look in - more generic to be more accurate and true to "hatchling" which in itself, implies ALL creatures "born" from eggs.