OK, my bees this year have been some swarmy son of a guns. I know the normal signs of swarms - multiple swarm/queen cells, backfilled broodnest, etc, - but I am stumped by one hive of mine. They had a single queen cell, which I took for supercedure and left in place, and they backfilled none of the brood nest. In fact, it looked like business as usual in the brood nest with a large amount of uncapped and capped brood. Do they always backfill the brood nest? Now that I think about it, there were some bees bearding near the entrance, but it was also 100 degrees that day. Do they swarm without warning sometimes?