Shoots flock or piece of clay (8)
I believe the answer is:
potsherd
'piece of clay' is the definition.
'potsherd' can be an answer for 'piece' (potsherd is a kind of piece). I am not certain of the 'of clay' bit.
'shoots flock' is the wordplay.
'shoots' becomes 'pots' (I can't justify this - if you can you should believe this answer much more).
'flock' becomes 'herd' (I've seen this before).
'pots'+'herd'='POTSHERD'
'or' is the link.
Can you help me to learn more?
(Other definitions for potsherd that I've seen before include "Piece once fired" , "A broken piece of earthenware in archeology" , "Pottery fragment; the drops (anag.)" , "bit of china" , "part of vessel found in digs" .)