Originally Posted by Natalie_ca
I don't know about a 5 month old kitten. But an older cat can have bad breath from: Diabetes, renal failure and bad teeth. Possibly other things too.
For a kitten it might be that he has a build up of gas in his tummy from the foods fermenting. Maybe try a different food and see if that helps?
Thanks, that could be. Unfortunately, a different food is not an option right now. He has food allergies and is two weeks into a chicken free diet trial. Trying to find a food that doesn't contain chicken is near impossible, and so far he has no vomiting and diarrhea on this one. According to the vet he needs to stay on this food for 8-12 weeks to know if chicken is officially the problem.