Favouring mature fodder (6)
I believe the answer is:
forage
'fodder' is the definition.
(I know that forage is a type of fodder)
'favouring mature' is the wordplay.
'favouring' becomes 'for' (to be 'for' something is to be in favour of it).
'mature' becomes 'age' (synonyms).
'for'+'age'='FORAGE'
(Other definitions for forage that I've seen before include "sort of cap" , "Look for food" , "Military raid" , "look around" , "Search widely for food" .)