Sheep bit castle defenders here? (7)
I believe the answer is:
rampart
'castle defenders here?' is the definition.
(a rampart is a defensive wall of a castle)
'sheep bit' is the wordplay.
'sheep' becomes 'ram' (male sheep).
'bit' becomes 'part' (I've seen this before).
'ram'+'part'='RAMPART'
(Other definitions for rampart that I've seen before include "Pain-relieving drug" , "Battlement, fortification" , "Broad defensive wall" , "defencework" , "Defensive structure" .)