Showing signs of damage in chicken run (7)
I believe the answer is:
scarred
'showing signs of damage' is the definition.
(with scars)
'in chicken run' is the wordplay.
'in' indicates putting letters inside.
'chicken' becomes 'scared' (chicken can mean cowardly or scared).
'run' becomes 'r' (cricket abbreviation).
'scared' going around 'r' is 'SCARRED'.
(Other definitions for scarred that I've seen before include "Marked (by wound)" , "Flawed" , "Bearing the marks of wounds" , "bearing evidence of injury" , "Blemished" .)