I've already found a vet, and I'm planning on taking all of them tomorrow.
Would it be horrible if I just asked the breeder for my money back so I can pay for their treatment, because I'm not returning the snakes? However, I don't know how to prove mites, because as soon as I saw them I killed them as well as I could. I didn't spend the time to try to take pictures, ha ha. Anyways, I don't want to send them back to a bad breeder. He came recommended by a friend, but I'm not so confident anymore about that.