The immune system of kittens is less developed and therefore more fragile than older cats. Although they receive some natural immunity from their mothers while nursing, they are generally more susceptible to disease than adolescents and adult cats. “It is best to stick to a kibble, canned or freeze-dried food for kittens,” notes Dr. Ochoa. “They tend to not eat all their food at one time. This can lead to bacteria growing on the raw food while its waiting to eaten.”