I have a swarm that just flew out of one of my hives. If I put it in a hive box, can I place it right next to its original hive without any problems?
I keep swarms in the same yard until I got a place to move them to. Not right next to the hive that swarmed, but real close and never had a problem.
If you put them right next to each other, you'll get some drift back to the original hive. I'd place them elsewhere, if your space allows. Also, I'd give them a frame of brood from the original hive to keep them anchored in the new deep.