When To Feed Kittens Cat Food?

I guess I can't swear that the same thing will work for everyone but I've always let the cats figure that out for themselves. At least my experience has been that the mother cat will do a pretty good job of deciding when enough is enough, leaving it for me only to be sure that an alternative food source is available. When my cats have decided that they were tired of nursing their kittens, they'd spend more time up high where the kittens couldn't get to them, and that was the time to introduce them to cat food.