Stray duck eaten by farm animal (4)
I believe the answer is:
roam
'stray' is the definition.
('roam' can be a synonym of 'stray')
'duck eaten by farm animal' is the wordplay.
'duck' becomes 'o'.
'eaten by' indicates putting letters inside.
'farm animal' becomes 'ram' (I've seen this before).
'o' going inside 'ram' is 'ROAM'.
(Other definitions for roam that I've seen before include "'Wander, ramble (4)'" , "Wander freely" , "Wander widely" , "Travel widely" , "Move about aimlessly" .)