Productive hen always held in both hands (5)
I believe the answer is:
layer
'productive hen' is the definition.
(I've seen this in another clue)
'always held in both hands' is the wordplay.
'always' becomes 'aye' (archaic term for 'always').
'held in' means one lot of letters goes inside another.
'both hands' becomes 'LR' (abbreviations for left and right).
'aye' inserted inside 'lr' is 'LAYER'.
(Other definitions for layer that I've seen before include "Thin sheet - productive hen" , "One supplying eggs" , "Stratum; chicken" , "Source of eggs" , "Bed - hen" .)