At this young age, being separated for a month or so really isn't going to cause that many issues. Your birds will all be young enough they're not invested in holding a specific order, they're still figuring out who's boss of who at this point. Go ahead and put the big girls out, then finish brooding the littles and add them. There will be some squabbling, but really no more than they do when they're all together to determine who's boss.
