A scraggly looking hen

[DoxonFarms]

I have one scraggly looking hen of my 58 layers, all are under a year old. I do have a RIR rooster, and I am thinking he's the problem but I dont want to place the blame and cull him if its not him. Most the birds are about 3 months old. This one is an ISA Brown, I think. Any ideas beside it's the rooster? I attached 2 pics of the scraggly hen and a image of what the rest of the flock looks like.

 

[MrFluffyandGirls]

Do you see the rooster on top of her and holding her down with his beak. You would see if it was the rooster doing the damage, they aren't to secretive when roughing up a hen.

 

[DoxonFarms]

No, but I check them at 5am and make sure waters and feeders are full, when I get home around 5ish to open the barn and let them free range, grab eggs and what not. Night checks- close them up for the night is around dusk after I get my kids in bed.