Yesterday in the middle of the day my daughter touched their perch inside the coop and tons of mites were crawling on her hand. Does that lead to NFM because they were active in the day, or red mites bc they weren’t on the bird? I looked in the daytime today and only saw one mite on the nesting boxes but I cleaned and put DE in the coop yesterday. My hen who was sitting on the eggs let me check her and there were mites in her tail and vent area that were moving around.
It can be either but my guess is NFM. The fact that they're active on the hen during the day is my main criteria (and yes they can be on roost too). Scrap the DE, it's obviously not doing a thing.
Also for time being I'd keep your daughter out, mite bites can get pretty nasty. I'd recommend only one person handle the birds until it gets cleared up, because we even got them in the house. Here's how I managed it, to try and minimize their impact inside: https://www.backyardchickens.com/threads/evil-chicken-mites.1354517/#post-22342505