Drink to a rooster-follower! (8)
I believe the answer is:
cocktail
'drink' is the definition.
(cocktail is a kind of drink)
'rooster-follower' is the wordplay.
'rooster' becomes 'cock' (synonyms).
'follower' becomes 'tail' (tail is a kind of follower).
'cock'+'tail'='COCKTAIL'
'to a' is the link.
(Other definitions for cocktail that I've seen before include "Screwdriver, for example" , "Manhattan, for example" , "Screwdriver, for instance" , "Possibly old-fashioned" , "dish with prawn" .)