This is my fourth year keeping bees. I currently have 10 hives. Several weeks ago, I noticed that one of my hives was queenless and there were laying workers in the hive. I gave them young brood and they successfully raised a new queen. However, four more of my hives are now queenless. Two of them are from packages that I just hived two weeks ago, one is from a primary swarm from one of my own hives, and the last is a three year old hive that had been requeened just last year. What is going on? What is happening to my queens? Please help!! P.S. Two other hives also lost their queens(presumably to swarming) but built queen cell in time and replaced her.