I am not sure what kind of "medical proof" you need. I think the basic requirements for a ferrets nutritional standards are pretty well known... although higher levels are debatable I think everyone agrees that a ferret needs: Minimum 34% Protein Minimum 18% Fat Everyone also agrees ferrets are carnivores and the protein source must be meat correct? The 8in1's food that is sold in the small boxes at WalMart has: Minimum 28% Protein Minimum 8% Fat The Kaytee and Nutriphase foods: The levels LOOK okay but look at the sources of the ingredients: Poultry Meal, Fish Meal, Animal Fat, Soy Flour, Kibbled Corn, Dried Beet Pulp, Dried Blood Meal. Ferrets are OBLIQUE CARNIVORES.. not Herbivores or even Omnivores... they must have a meat source for protein. Hunks of dried fruits and vegetables should not be in their staple diet. I have witnessed dozens of ferrets who were "fine" on these foods get switched to better quality foods and the owners amazed at how much better they looked, how much more active they were etc etc etc I have watched 7 ferrets in the past 8 months who were all fed these foods for years dies of complications that the vets marks down as "due to inadequate food"... there has been numerous studies of ferrets and nutritional needs which all say the same thing. Exactly what more "proof" was needed? Am I saying no ferret fed these foods ever lived a good long healthy life? No of course not... we are talking percentages and odds here. Does every single person who smokes cigarettes die of lung cancer? No... but are the percentages higher? Yes. Saying a vet told you so, in my book is not good enough. I know vets here who tell people generic cat food is okay and that ferrets get vaccinated for Feline Leukemia... just because someone is a vet doesn't mean they have followed the research on ferrets. Let's look at vet knowledge: A vet here see's ferrets and "treats" ferrets. We are currently in an argument with someone to get another vet to look at their ferret. An almost 5 year old Marshall Male who suddenly stopped using his litterbox, is having trouble urinating, and is sexually attacking the other ferrets. This wonderful vet told the person this is NORMAL behavior and not to worry about it... now she refuses to believe me (who is not a vet) that I think the ferret had Adrenal Disease and to get a second opinion. [Posted in FML issue 3161]