Turkey feed to subject to a process (5)
I believe the answer is:
treat
'process' is the definition.
(I know that process can be written as treat)
'turkey feed' is the wordplay.
'turkey' becomes 'tr' (abbreviation eg in internet addresses).
'feed' becomes 'eat' (I've seen this before).
'tr'+'eat'='TREAT'
'to subject to a' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for treat that I've seen before include "Entertain at one's own expense" , "Deal with - source of great pleasure" , "could be a feast" , "Act toward or regard in a certain way" , "Cure" .)