Why do kittens purr when they eat?
This is normal animal behavior; it's a sign of food guarding, a fear of having food taken from other animals. When kittens are eating, owners should try not to disturb them, as this could lead to indigestion. 
Kittens often make sounds to express themselves. Purring means they enjoy being petted. Arching their back and purring indicates they're angry. Ruffled fur and hissing sounds mean they're scared or their territory has been invaded, and they're trying to intimidate the intruder.
