Eyesore? What some animals live in, we’re told (4)
I believe the answer is:
stye
'eyesore?' is the definition.
(I've seen this before)
'what some animals live in we're told' is the wordplay.
'what some animals live in' becomes 'sty' (as in a pig sty).
'we're told' shows a homophone (sound like).
'sty' sounds like 'STYE'.
(Other definitions for stye that I've seen before include "Eyelid affliction" , "producing eyesore" , "nasty spot" , "Tamworth residence" , "Infection on the edge of the eye" .)