Loosing feathers

[neilgal]

One of my girls lost her feathers on her back and a specially off her left wing.
It doesn't look like she is molting. She has been like this for four months without any change. She is very active and laying eggs normally.
I have been observed the other chickens non of them is picking on her.
I have been looking for information about this situation here and over the internet and I couldn't found anything.
What could it be?
Any suggestions ?

 

[chicks4kids]

If you have any roos She may be the roos favorite and he's wearing her feathers off. There are chicken saddles you can either make or buy to put on her until those feathers grow back in. But that's what it sounds like to me just from your description.