New to Chickens need help ID problem and how to treat

[firedogpotter]

Help we are new to owning chickens. I have two girls who have a swollen (inflamed?) rear end. They appear healthy otherwise, no respritory issues noted. Can anyone help identify what you see in this picture and how to treat it? I do belive they are still laying as we have 6 birds and got 5 eggs yesterday.

Thanks
Michael

 

[ChickenCanoe]

Have you checked closely for lice or mites?