Any ideas what’s going on? Hoping to treat ASAP

This is one of eight hens and she is the only one with the problem. She doesn’t seem too affected by it, really has been hanging out on the roosting bar every time I go out there. Many say it’s either mites or rodents biting at her legs. I checked the outside of the coop and didn’t see anything indicating a rodent forcing its way in. The run is surrounded by hardware cloth, a foot above and a foot below ground (not reflected in previous posts, has since been significantly upgraded). I use hay in the nesting boxes and pine shaves in the coop bed.