Animal in farm area (4)
I believe the answer is:
mare
'animal' is the definition.
(I know that mare is a animal)
'in farm area' is the wordplay.
'in' indicates the answer is hidden within the clue.
'MARE' can be found hidden inside 'farm area'.
(Other definitions for mare that I've seen before include "Adult female zebra" , "Horse; lunar sea" , "Adult female horse" , "Female quadruped" , "Female equine animal" .)