Thank you so much Bob! This is great advice...14 weeks, boy, you got a ways to go. At least he won't be real big. How much separation could you manage? If you could keep then apart but visible for a while and then start providing short supervised visits with the flock I think that might ease the flock through his growing pains. Just an idea.
I'm not sure how much you can take on. This will take your time as well. Otherwise the flock will figure it out eventually but it will likely be painful until they do.