kittens licking to pick on another

We have a litter of 8 kittens, about 6 weeks old.  Recently all of the kittens have started licking one kitten in the same spot continually.  We have given that kitten a bath---thinking there must be something on him, but they continue to lick him constantly.   Any ideas as to why? or what to do to prevent it?

I've seen cats lick one another for comfort, but that doesn't seem quite like what you're describing. You say they lick the one kitten in a particular spot? Could it be bleeding or having some kind of discharge and they're cleaning it?

IMO it would be a good idea to separate that kitten for a bit and watch to see if there's something wrong with it. If they really are picking on it for some reason, it should be separated from them for safety.