What non-prescription food/treats do you give your cat with kidney issues? - eviltoast

Our 20-year-old has CKD and we feed him a prescription food in the morning (Royal Canin Renal Support D) and a non-prescription food in the evening (Forza10 Renal Support paté).

Treats are limited to catnip, cat grass, and the very rare small piece of plain chicken.

What do you feed yours?