Hens Pecking My Rooster

[D SCHWARTZ 26]

Hello,
I recently bought 12 Isa Red Ready to lay hens. I let them settle in then I put my rooster (who is around a year old and is an Americana cross breed) in with them. They really seam to like him but they peck at him a lot and he is starting to loose feathers all around his neck and shoulder areas. I'm not sure what to do. He doesn't seam bothered by them pecking at him so I don't think they are hurting him but worried they are going to start. I attached some pictures of him.
Thanks.

 

[Colonel-Sanders]

Well since he doesn't seem distressed about it the only thing I can think of to do is separate him from the hens for a week or two so he can get his feathers back.

 

[sannabelle]

Is there a particular hen or hens that are doing it? Or all of them?

 

[D SCHWARTZ 26]

It seams to be all of them but they all look the same so I can't really tell them apart :/