Which one do you have? If it's k/d, I know there are a couple of different varieties (flavors/textures) of it. Pate is usually more palatable for the kidney kitties. I have the chicken one, Sara loves that one.
What did you get? Birdie is nt eating the low protein presciption food.
You probably want to focus on the phosphorus more than the protein though. That's part of what makes them feel like crap.