I have ferrets with kidney problems (older ferrets with kidney problems- start of kidney failure). I have put them on Hills Feline KD diet which you have to get from your vet. It comes in cans and kibble. I usually take 1 cup of kibble and add 1 cup of water to soften it and let it soak overnight. The next morning I put it in a blender and add a can of the HIlls Feline KD canned chicken chunks (they like this not the plain canned KD) and blend it well till like a chowder. I give this to my ferrets with kidney problems and add a little bit of Gerbers stage 2 turkey baby food (tsp) 4 times a day - they get about 3 TBS 4 x daily with their pred or whatever medications they are on. EVERYONE'S kidney's values HAVE IMPROVED !!!! Please try it. You will need to warm the servings before feeding them. You may also have to finger feed to get them used to it. Or you may have to mix what they are on now slowly to this new formula. It has helped my kids! I have one guy who was diagnosed with kidney failure almost a year ago and his values did improve after this diet ( his urine was clear at one point ) and now his values are still pretty much the same! After all he is almost 9 years old! He will be in January! I have 4 ferrets on this mix. 3 have Bobs chicken gravy, just a tiny bit mixed in with it for extra vitamins after I weaned them off of the chicken gravy and onto the kd. I add a little more water to the soup before heating it up so it is not thick but not real watery either. When I fed them at 6 tonight, I realized they get about 2 Tablespoons if even of food at a time, it depends on the ferret and their individual appetite. Some get fed 3 x daily and others 4 x daily, depends on medications they are on and if they have insolinoma. There is so much water in their soup that they do not really need any extra water. I rarely see them drink water also. That is why I add water to their soup. I am glad Ruby is doing better. My old guy Winter who is almost 9 also has colitis so he is on a mix of Feline KD and Hills Feline WD which is high Fiber, I believe, for his colitis (just in case you should ever have a ferret with colitis). Good luck and I am sure Ruby will do just fine in your care. p.s= my vet suggested the feline KD and feline KD for the ferrets and it comes in kibble and canned, available only at your vets. Eleanor, Donald and the 9 fuzzies, missing Sarah and Cooper J Eleanor Mead [P.P.S.] forgot to let you know to always keep refrigerated once water is added to kibble to be soaked overnight and of course after it has been mixed. This mixture stays good for up to five days once mixed in containers in refrigerator. [Posted in FML issue 4666]