My girls have mites?

Made a post a few days ago about my girls losing feathers, and I thought it was my rooster. I have an appointment to bring them in Wednesday to make sure and get the proper stuff to take care of it.

I tried premethrin but it’s not doing shit. I cleaned their coop out, and even sprinkled a bit of dt on everything (not to much) but one girl in particular is almost non stop picking herself. I’d like to help them in the meantime. What can I do? I feel awful