Can you see bugs on them or not?
If you can see actual bugs on them (little red things that move), they aren't mites they are lice. If they are scabby and losing hair, but you can't see anything, then mites.
In the case of lice. You can treat them with advantage (for dogs or cats, we used cats because we had it), one drop around the shoulder blades.
Now if I remember right. Advantage won't treat mites, but Revolution will. Revolution you may have to go to a vet to get.
Ivermectin will I believe treat both mites and lice. For dosing you can squeeze some out onto a plate, and get it into a dose about the size of an uncooked grain of rice.