Help for an Early Swarm

[DennisBEEK]

My buddy and I who are neighbors re-ordered 2 packages of honey bees following winter kill-offs in both our hives last year...our first year. My buddy set his hive up again in his backyard, and I set mine up again on top of my flat-roof building. Our bees arrived Monday and we unloaded them. That same evening, my buddy's next door neighbor expressed disappointment with the discovery of his hive and its location near his fence. Considering that there are a couple of smaller kids in that yard, my buddy and I wrapped his hive in plastic yesterday evening and carried it off to my roof where we set it up about 25 feet away from mine.
Today, Wednesday morning, my buddy noticed a swarm had formed on the cedar fence near where he had originally place his hive. I immediately checked his hive and found plenty of bees still in the back of it. We could not determine the location of the queen. This evening, we captured most of the swarm and moved it back to his hive on my roof. I should also point out that he had forgotten to move a bit of last year's honey that he had placed just outside the hive's original location and some of the bees from the swarm were feeding off of it.
My questions are:
Why did this apparent partial swarm occur...especially considering he had placed some additional honey from last year inside his hive?
I know it is not a good idea to move a hive once the bees have been unloading, but do you think they will swarm again soon?
Any comments, thoughts, or suggestions are appreciated.

[Aram]

How far did you move the hive? I doubt it's a swarm. They are probably worker bees who forgot where they left in the morning and returned to yesterdays home. Some will return again tomorrow and the day after. You can help them by placing some leafy branches in front of their entrance or find some way to slow them down and take notice of the new location. They have to reorient or else they leave in hurry and can't find their way back.
If you have a nuc with some wax foundation you can place it at the old location. The lost bees should snuggle inside and you can transport them to the new location with minimal disturbance.
I'm not sure what "forgotten to move a bit of last year's honey" means. You mean he left a bar with comb behind, when you moved the hive?

[DennisBEEK]

We moved his hive about 100 yards from his backyard to my rooftop. His hive is now about 25 feet away from mine.

[DennisBEEK]

Also, Aram, the honey we used was from last year's production. We simply broke off some comb left over on some of the top bars and used it to feed the new bees.

[Aram]

@ 100 yards you'll definitely have them come back for a few days. But there will be less every day and not too far to transport. Pile their entrance with leafy branches as I said. It helps a lot.
Good luck,
Aram

[Stevedore]

You could also try shutting them in the hive for 48 hours and reopening the entrances at night. Jay Smith claims that this will cause most bees to reorient to the new location.