Chicken is served with rook hearts and hock (7)
I believe the answer is:
rhenish
'hock' is the definition.
(I've seen this before)
'chicken is served with rook hearts' is the wordplay.
'chicken' becomes 'hen' (hen is a kind of chicken).
'served with' is a charade indicator (letters next to each other).
'rook' becomes 'R' (chess abbreviation).
'hearts' becomes 'h' (abbreviation used in card games e.g. bridge).
'hen'+'is'='henis'
'henis' after 'r' is 'rhenis'.
'rhenis'+'h'='RHENISH'
'and' acts as a link.
(Other definitions for rhenish that I've seen before include "- - Wine (hock)" , "from a particular flower?" , "Hock - relating to a European river" , "Herein's Schumann's Third" , "eg Hock" .)