So I have two male rats that I bought back in June at a pet store that was not taking care of them. I took them straight to a local exotic vet who diagnosed the babies with URI and said that they will most likely have myco issues the rest of their lives. I have since moved and have had some trouble finding a reliable vet. The last vet I took too I have more confidence in than most in the area but I am still unsure. He said my Scabbers was not experiencing a myco flareup like I had thought but an allergy to his bedding. (I use care fresh) He said there is some ingredient in it that begins with a V that he has noticed many ratties are allergic to. He also suggested I switch the bedding to aspen. Has anyone else ever heard or experienced this? Is aspen safe for rats? He has been sneezing a couple of times a day but it seems to be a dry sneeze like an allergy would be. I just want to be sure he doesn't need an antibiotic because if he does I of course want to take him to another vet asap. My other rat Carl never seems to have any problems and the only time he has sneezed more than once in a blue moon was when I first got him from the stupid pet store.