Sheep's flesh not being cooked for dog (4)
I believe the answer is:
mutt
'for dog' is the definition.
(mutt is a kind of dog)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for mutt that I've seen before include "Mongrel - fool" , "Thematic type [DOG]" , "Dog of mixed breed" , "far from best in show?" , "Chump" .)