Weight/hair loss in 3 year old, neutered ferret

Question
I have four ferrets, ranging from  8 months to about 3 years old. My (around) 3 year old boy went for his vet checkup/distemper shot in August. I told the vet I was concerned about his weight being down, and his coat being thinner (mostly in the rat-tail appearance). The vet said he felt no tumors, that the weight/hair loss was probably seasonal, and to bring him back in if the winter didn't find him back to being his normal self. While it's technically not winter yet, and funds are very tight, I don't want to take him in for an unnecessary appointment.However, his appearance seems to be drastically changing. I found what appears to be black, tarry stools by one of the litter boxes (I currently have him segregated from the others to determine whether or not it came from him). When I pick him up, he seems to be skin and bones, where last year at this time he was a chubby little fluffball. I don't feel any obstructions in his stomach, and he seems fine with letting me feel around for them. I haven't noticed any tooth grinding or vomiting. A google search on Tarry Ferret Stools suggested gastric ulcers, but I don't think this would include hair loss... My first thought with hair loss was adrenal disease, but he was tumor free two months ago, and doesn't have that "pot bellied" appearance, just super skinny. I'd appreciate any advice I can get on how to care for my little one, or what kind of vet cost/diagnoses I could be looking at. Thank you for your time!

Answer
I can't really answer this as I am not a vet but I can address some issues.  I don't know of any ferret vets that can simply feel for an adrenal tumor.  Some run a blood panel, but most go with symptoms and treat for adrenal.  Now, we are using Lupron or Deslorelin.  the dark tarry stool sounds like an ulcer is a possibility and needs to be treated ASAP.  Sometimes they can have both an ulcer and adrenal and sometimes hairloss is the only visible sign of adrenal, but in a 3 y/o I would assume adrenal.