Mounting or mites? Missing feathers and irritated skin - help! Dx and tx options?!

[Lmstephenson11]

Over several months my girls feathers were being lost on back and then around throat. Thought it was molting but now it’s worse, red and agitated. Separated her from other chickens and treating her with Veterycin to see if it will help with the agitation and redness but wondering if she has mites or something else? Can’t see anything on her. One or two other chickens are starting to lose feathers on back but barely and nothing like this girl. Help!!

 

[JustAChickenLoverOverHere]

Looks like severe over mating or maybe mites. Have you inspected her feathers?

 

[Lmstephenson11]

I’m not noticing anything in her feathers. It’s also around her throat/neck so I wasn’t sure it was overmating.