hens bald spot on back ?

[BjAngel]

Hi everyone I was left with some chickens from my stepfather. My question is some of the hens have bald spot on their back at first I thought it might be because he has to many roasters (2) and not enough hens in the run (5) could the bald spots be from mating.

 

[sourland]

Very likely that it is mating damage.