ok so its a two deep land that was over wintered and doing great. week and a half ago there was piping, so i took some brood and the queen, and put them in a nuc in an out yard. four days ago i went through the hive and found an open supercedure cell but no new brood. no eggs no larva. couldnt find the queen but i think she was in there. so today my friend where the hive is called me and said that they swarmed out, clustered, then they went back to the hive. i stopped by after work today and theres a nice full hive of bees and some girls still fanning out front. not ventilating, marking their new home. so near as i can tell there was just one queen, they swarmed, got some fresh air, and went back home. soooo, what gives? why would they swarm with just one queen and then go back home?