What kind of food are you feeding them? You may want to try softening it until they get used to it better, if you already haven't. What I had to do when my dog's puppies were ready to wean, was just keep them seperated. I know it's harder with cats, cause the little stinkers and jump over everything! I've also heard of buying the same thing people use when they don't want their small house dogs to mark everything and putting it around the mom's belly. It looks alot like a sleeve with velcro.