Sounds like absconding behaviour. If it was you will have a basically empty hive with brood left behind.
If it was a swarm then they are most likely done for a while. Crowding is the cause of swarming 99.9 % of the time so be sure your other colonies have room.
If it was a swarm then they are most likely done for a while. Crowding is the cause of swarming 99.9 % of the time so be sure your other colonies have room.