Duck on rolls to follow feast (5)
I believe the answer is:
eider
'duck' is the definition.
(eider is a type of duck)
'on rolls to follow feast' is the wordplay.
'on' becomes 're' ('on' can be mean 'with reference to').
'rolls' is a reversal indicator (I've seen 'rolled' mean this (letters roll back)).
'to follow' means one lot of letters go next to another (some letters go after or follow others).
'feast' becomes 'eid' (feast in Islam).
're' back-to-front is 'er'.
'er' after 'eid' is 'EIDER'.
(Other definitions for eider that I've seen before include "Down comes from this" , "Duck from which down is obtained" , "Down's source" , "Species of duck" , "Large sea duck" .)