Film about a hen? (5)
I believe the answer is:
layer
I believe this clue is a double definition.
'film' is the first definition.
(film can mean a thin layer of something)
'a hen?' is the second definition.
(something which lays - eggs in this case)
'about' is the link.
(Other definitions for layer that I've seen before include "Productive chicken" , "Source of eggs" , "(Separate) level" , "Coating" , "Stratum, tier" .)