Heard local sound of sheep (3)
I believe the answer is:
baa
'sound of sheep' is the definition.
(I've seen this before)
'heard local' is the wordplay.
'heard' shows a homophone (sound like).
'local' becomes 'bar' (I've seen this before).
'bar' is a homophone of 'BAA'.
(Other definitions for baa that I've seen before include "Sound from a ewe" , "Cry of a sheep" , "Bleat of a sheep" , "Call from Jacob" , "Statement from those flocking" .)