Most appropriate accommodation for a farm animal (5)
I believe the answer is:
beast
'farm animal' is the definition.
(as in a beast of burden)
'most appropriate accommodation for a' is the wordplay.
'most appropriate' becomes 'best' (best-suited).
'accommodation for' indicates putting letters inside (some letters accommodate others).
'best' placed around 'a' is 'BEAST'.
(Other definitions for beast that I've seen before include "Savage" , "Inhumanly cruel person" , "Inhuman person" , "Bully" , "Nasty type" .)