I just released a new queen (she had been in the hive in cage for 3 days and they had not released her) into a queenless hive with a very small cluster, and added a frame of BIAS from another hive. When I put my ear to the hive afterwards, I almost jumped! There was the strangest - very LOUD - low-pitched stuttering buzz coming from the hive. Never heard anything like it - any thoughts? It was not being made by a group of bees, sounded like just one. Hope it wasn't the queen being attacked...