Will Falconer, DVM Moderator
Hi Sarah,
It's unclear to me if she's making new stones, but she sure has a lot up there in the kidney pelvis, it sounds like. That sounds like a surgery waiting to happen.
You might do better to use your raw food on your other cat. No need to be nervous about creating problems there. You'll only do good for her.
As you might imagine, cats in the wild (the big cats being the most useful model to study) aren't needing stone surgeries. And they eat one food: prey. The closer you come to that in your domestic cats, the healthier they'll be. But start with the low hanging fruit: your cat who's not made stones yet. Stop back after a month of feeding like this, and I'll bet you'll have an inspiring story to tell!