Should be fine. They will bat the crap out of the kitten occasionally but it normally looks far worse than it is. If they get too harsh throw a shoe at them or something until they get the message.

besides kittens are too cute to stay angry with even if they shit everywhere, the old boys will get used to it. I think the main thing is they wont see a 4 inch long fluff ball as a major threat to their pecking order and have to kill it.

Its probably just as likely that they will refuse to go anywhere near it for a while....