Not all fowls may be found in barns (4)
I believe the answer is:
owls
'found in barns' is the definition.
Although both the answer and definition are plural nouns, I don't understand how they can define each other.
'not all fowls may' is the wordplay.
'not all' indicates a hidden word.
'OWLS' is hidden in the letters of 'fowls may'.
'be' is the link.
Can you help me to learn more?
(Other definitions for owls that I've seen before include "Night birds" , "Slow sort of birds" , "Avian symbols of wisdom" , "Members of Parliament" , "Nocturnal birds" .)