Strata in hen society? (6)
I believe the answer is:
layers
'strata' is the definition.
(I've seen this before)
'hen society?' is the wordplay.
'hen' becomes 'layer' (something which lays - eggs in this case).
'society?' becomes 's' (common abbreviation in names of organisations).
'layer'+'s'='LAYERS'
'in' is the link.
(Other definitions for layers that I've seen before include "bands" , "Those preparing" , "fowl?" , "Shoots" , "Levels" .)