Minnie lost the fur under her neck and belly and over her temples when she was a year and the vet said she had chihuahua pattern baldness and there was nothing I could do. I eventually switched her food to Acana and her fur has really filled in on her chest and belly. Minnie didn't have any odor and it sounds like your little guy has something else going on. I only wanted to mention this because I have seen the improvements a good quality food can have. Hope you little ones hair loss mystery gets solved and gets better!