Poem for the last hog and sheep (7)
I believe the answer is:
epigram
'poem' is the definition.
(I know that epigram is a type of poem)
'the last hog and sheep' is the wordplay.
'the last' becomes 'e' (I've seen this in other clues).
'hog' becomes 'pig' (synonyms).
'and' means one lot of letters go next to another.
'sheep' becomes 'ram' (male sheep).
'e'+'pig'+'ram'='EPIGRAM'
'for' is the link.
(Other definitions for epigram that I've seen before include "Witticism - adage" , "Witty poem" , "Old chestnut" , "Short, memorable saying" , "Sally perhaps" .)