piggy health

Question
IHi, I have been keeping piggies as pets for about 10 years now. I use them in my classroom. I rotate them every week. I have 6 females and they each take a turn at school for the week. They have been one of the best things I could of brought into the classroom. The kids are very responsible and caring with them. Anyway, I do keep them in a pen outside when they are not working. I believe they have mites. About 5 years ago I had an infestation and had the vet give them all a series of shots. I haven't had this problem again until now. I recently took in two rescue pigs and noticed hair loss on a patch on one of its back. I now have a couple of piggies showing signs of hair loss, small scabs,itching. I saw no sign of lice. Is there anything I can use on them that I can do at home? Or do I need a vet to give them ivermectin injections?
Thank you,
Denise

Answer
They need to have ivermectin injections from the vet.
Also, why are you keeping them outside? When they are at home,are they inside? What kind of cages do you use and how big are they? What kind of bedding are you using? What are they getting to eat?

Mites are usually caused by stress. The cavies are probably getting stressed out from going to and from school everyday.