One that kills headless chicken, potentially? (5)
I believe the answer is:
layer
'one that kills headless chicken potentially?' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
This is the entire clue.
Can you help me to learn more?
(Other definitions for layer that I've seen before include "plate?" , "Single thickness and hen" , "Stratum, tier" , "Blanket - single thickness" , "One of several thicknesses" .)