Chery has four kittens, 3 big juicy ones and one that is much smaller. Everyone seems happy enough, but sometimes when I look in the box, the 3 big ones are eating, and the little runt is squirming around trying to get up to the milk bar. There are 8 choices, so what is the problem? He is behaving normally, how can I be sure he is getting enough milk? Weigh him?