Mites or Stress?

From what I've read, stress can cause mite outbreaks to go from 0-60 and can also cause quilling. How do I know the difference? One of my guys is quilling like crazy and both are itchy. We just had an cage change, so I know stress is a factor. I've never had to deal with mites or really stress quilling to any worrysome degree. I've made an appointment with a vet but they couldn't get me in for 2 days. Also, one of my guys' health is declining anyway, as he's nearly 5, so I really don't want to put him through a vet visit if I don't have to especially if it's stress to begin with. Any suggestions on telling the difference?



Note: we are a fleece family, so no shavings here!