Has anyone experimented on ways to try and keep them?
I hope that you ask this:
I have wondered same thing, why swarm abandon the hive if queen have even laid some eggs.
I have learned something:
* some bees are mad to swarm; when I have get it into deep, they rises on they wings at morning -- why, dont know? It is rare.
* I have put swarm in too hot place and I have feeded at once. Bees feel too tight and move away.
* I have read that there is no sence to feed swarm at once. They have 3 days food with them and let them consume that first.
* If they have foul brood spores in they honey stomach, it is better that they consume honey all and do not store it.
* Keeping swarm in dark chilly place 24 hours calm the swarm and it stays better in the hive.
I have met situations when swarm collect so much honey during it's first week that space is full and swarm leave the hive again. When the room for eggs is full, bees goes away.
After rainy week swarm may have several queens (4-5) and it is difficult to catch them. Swarm may devide itself into several groups.