Do my pet rats have parasites?

[Mavismay]

I recently noticed that My Male pet rat Zeppelin has small patches where there is no hair. There is one patch near his left ear, and 2 on his back. The patches are small but they are noticeable if he stands up or stretches. His skin has turned orange (which is buck grease) so I’m wondering if that’s maybe the reason why? He also has some small scabs on his back. I don’t notice him clean himself as much as my other rat crouton. I also noticed both of my rats have been sneezing and scratching themselves quite a bit lately. I’m thinking they’re sneezing because I had to use pine shaving bedding (it isn’t good for their respiratory system but I ran out and I live in a small town it’s all they had) but they only had it in their cage for a week.

If it helps crouton is the more dominant rat and they are not fixed. when I first got them they both had mange mites which I treated. They are being fed Garden Select Oxbow for adult rats. I don’t think they have lice because I checked both of them and I didn’t see any eggs or live bugs.