In addition to Bob Church's chicken gravy (which I highly recommend and which you can modify for insulinomics by omitting the Nutrical and honey, FYI), Hill's Science Diet A/D food (which is only available through a vet, as it is a prescription food, but is pretty much available through most vets) is a great food for trying to bulk up and get nutrition into ferrets, cats, dogs... It's also gentle on the tummy. (You can try warming it in the microwave to help make it even more appealing to them, too, but I daresay the smell of warm A/D won't be too appealing to YOU! ;) ) Nutrical, if your guy is not an insulinomic, is another great high-calorie, nutrient-rich supplement available at your vet's office, and is generally well-received by the ferret set-it has corn syrup and smells kind of like molasses (not a good supplement for an insulinomic in general once you've gotten their blood sugar regulated, and should only be used VERY short-term as an aid in getting an insulinomic's blood sugar up-overuse in this capacity can cause worse problems). A vet tech and ferret owner, not a vet, April AC [Posted in FML issue 4482]