Switching food is extremely hard on their tummy. Sounds like a bit of canned pumpkin (not premade pie filling) would be beneficial to calm down his stomach. Charlie's tummy became upset from too much wet rabbit food (rich), and he had loose stools. Added pumpkin and he is fine today.
You might try a bit of warm water in his kibble to soften and bring out the flavor. Warmly, Deborah |