Consume stuffing with chicken — it's made from grain (7)
I believe the answer is:
wheaten
'made from grain' is the definition.
(wheaten means made from wheat grains)
'consume stuffing with chicken' is the wordplay.
'consume' becomes 'eat' (eating is a kind of consuming).
'stuffing' indicates putting letters inside.
'with' becomes 'w' (short for with).
'chicken' becomes 'hen' (hen is a kind of chicken).
'w'+'hen'='when'
'eat' put within 'when' is 'WHEATEN'.
'it's' acts as a link.
(Other definitions for wheaten that I've seen before include "Like bread" , "corny!" .)