Productive hen always in both hands (5)
I believe the answer is:
layer
'productive hen' is the definition.
(I've seen this before)
'always in both hands' is the wordplay.
'always' becomes 'aye' (archaic term for 'always').
'in' is an insertion indicator.
'both hands' becomes 'LR' (abbreviation for left and right).
'aye' placed into 'lr' is 'LAYER'.
(Other definitions for layer that I've seen before include "One of several thicknesses" , "Source of eggs" , "Productive chicken" , "One who does the setting" , "Blanket - single thickness" .)