Having hens raise the chicks is excellent way to have peafowl that stick around because peachicks form very strong bonds and will stick with the hen for a very long time, a full year, if the hen 'lets' them(hens usually start getting aggressive or avoiding their babies once they start laying again or go broody).
I used to do this every year, was always much less worrying than letting brooder raised ones loose, because the brooder chicks don't have any 'leader/teacher' so sometimes they will go where they are not supposed to while still very young.. Just doesn't happen with chicks following a hen.
It is best to keep hen and babies confined for the babies' protection because they are very vulnerable to hawks or creatures that like to eat small animals. Survival is way improved if they are let loose once they are past the size of those predators. I often kept mine confined 2-3 months before opening the door.
Depends generally on the age of new peafowl, younger birds take to new place easier and faster than older birds.. full mature adults are the hardest. 1-2 months for birds year old or younger, 3-4 months for 2-3 yrs and 6 months or more for mature peafowl. They are never strictly consistent.. some will still disappear, some matures will stay around forever even if they were simply tossed over the fence upon arrival.. so regard those as generalizations.
Also not good idea to bring in new adult male if there are adult males already on property, especially during breeding season. the best time is after they have shed their tails, when their aggression is at a low point.