jeeperspeepers: You should have no problem putting them with the mama, just wait till nighttime when she is sleeping. But you need to do it when all the babies are itty-bitty, and you need to make sure you are up the next morning before the hen leaves the nest, to watch and make sure she doesn't reject them.
As for putting them in the coop, if there is plenty of room for everyone, the mama will take care of the babies. But just like with putting new babies with mama, watch and make sure everyone will get along, it won't hurt mama to be locked up with the babies for a while longer if the big ones want to be butts!