Missing feathers

[PrincessChicky]

I have a hen that has lost the feathers by her tail and vent. At first I believed that the other hend were picking on her but now I'm not sure.
I have checked her for lice. I don't see any! So what do you think is causing this and how do I get her back to being nice and healthy? Thanks!

 

[Brahma Chicken5000]

I’ve heard of this happening before and it’s usually caused by the other chickens pecking the feathers out.