Feathery layer some strengthened (3)
I believe the answer is:
hen
'feathery layer' is the definition.
(feathered bird which lays eggs)
'some strengthened' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'HEN' can be found hidden inside 'strengthened'.
(Other definitions for hen that I've seen before include "Female lobster, fowl" , "Female bird" , "Domestic egg layer" , "Insufficient in amount" , "Composed of women" .)