Karen, I'm no vet, but I still believe your ferret has adrenal symptoms and should probably be opened up. (BTW, is he Marshall Farms -- two blue dots on right ear?) I do believe most hair loss occurs from bottom end up, but each animal is individual and I would take that into consideration. Plus, you did mention that the hair loss is bilateral, and with adrenal problems, usually is. The lethargy you mentioned is also a symptom of adrenals (as well as many other diseases), but the one key thing you mentioned was he was getting "heavy". Do you mean he's actually getting heavier, or he's beginning to develop a pear shape when you hold him up? The pear shape (as well as loose skin around the back legs) is another symptom. I only know cause I've been through it, and helping out at a shelter have seen it many times. Good luck! Amy & Dave (and their gaggle of giggling ferrets) RIP Ian and Elektra [Posted in FML issue 1627]