fur care

Hi guys, My lovely teddy sow seems to be missing some of her fur on her back / rump area. I haven’t really seen her itching or anything so don’t know if it could be mites. Just wondering if anyone has any ideas?

Advice needed please! We have 2 girl guinea pigs around 2 or 3 (unsure as rehomed) & they have got hay mites! This is the second time they’ve had them, when we got them in February they came with the mites. We bathed them & put treatment on and thought that would be it but now we’ve noticed...