Loss of feathers on chest

[cgasich77]

One of our girls has some redness and loss of feathers on her chest area. It doesn’t seem to bother her and she’s always the first one at the gate to greet me looking for food. I’m wondering if this is common or if we need to treat it with something. Newbie here. We adopted this flock a few months ago and they’ve been together for a long time prior.

 

[Bcoz18]

So mine had the same thing but on her bottom if you look closely around the remaining feathers it maybe that she has mite/lice. I was able to get ahold of mine and mine had either mites or lice so I treated with permethrin 10 and I have one more treatment once it gets below 100degrees here I'll do another coat.
I'm not professional though