Not an egg-layer, but a crow producer (7)
I believe the answer is:
rooster
'crow producer' is the definition.
The definition and answer can be both animals as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for rooster that I've seen before include "one going to sleep" , "Adult male chicken" , "So retro (anag.)" , "Farmyard cock" , "Farmyard bird" .)