Hirsute officer set about devouring contents of egg (6)
I believe the answer is:
foetus
'egg' is the definition.
The answer and definition can be both animals as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
'hirsute officer set about devouring contents of' is the wordplay.
'hirsute officer' becomes 'fo' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'about' is an anagram indicator.
'contents of' says to take the centre (I've seen 'content' mean this).
The middle of 'devouring' is 'u'.
'set' mixed up with 'u' gives 'etus'.
'fo'+'etus'='FOETUS'
Can you help me to learn more?
(Other definitions for foetus that I've seen before include "Developed mammalian embryo" , "Unborn child" , "Embryo in later stages" , "Embryo of a mammal" , "Developed embryo in the womb" .)