Mites or something else

I'm not sure if this is where I need to ask or under diseases.

I lost my welsummer rooster last Thursday, I seen that he was hanging in the barn and not in the coop at night and was breathing a little heavy. I know he got into it with my other rooster, who was the beta rooster, about Sunday of that week. Thursday I went out to close them up and I could not find him. I found him Friday morning and took care of him.

Well Sunday before I went to work my roosters hen(they were good friends) was standing by herself. Monday I checked her out and she looked like she might of had a pasty butt and the area was bare and I seen one mite which could be normal. She had laid me an egg earlier so I know she is not egg bound. She was lethargic and the other chickens would not let her eat. I took her aside and feed her some oatmeal and put her back in the coop. I checked on her this morning and she was sitting in the corner under the roosting area. I again checked for mites but did not see anything so I put her in a cage and gave her oatmeal and water. When I got in the house I san mites on me. It is Still making me itch and I am finding one or two here and there on me. I took wood ash out to her and cover her with it and put a bunch in the coop and nesting boxes.

I am planning on getting seven later and dusting all the chickens tonight. I am concerned that it may not be mites and something else I have lost 2 other chickens this winter (3 altogether one was old, one was 4 yrs and the rooster was 2yrs)and now I am getting concerned that maybe I have a virus

any suggestions

I also had a problem with possums this winter - I still have one that was hanging in the barn.

Is their area clean? And not a land full of poop?
I would definitely dust all your chickens, and put DE(diatomaceous earth) In their food
Here is a link to the benefits of DE
https://www.diatomaceousearth.com/diatomaceous-earth-chickens/

I use DE and none of my birds or dogs have mites or parasites.

Hope this helps

BCP

I just cleaned it out about a week ago. I knock off the top layer and put down new during the winter but I removed 98% of it a week ago. I will start treating it as a mite infestation and be more diligent in the future. It is going to be a long struggle for they free range and are into everything.

thanks for your input.