There are exceptions to all rules – and I believe that others have found an exception to this rule. But I have not. So far as I am concerned this rule holds true: that there is only one Queen Bee in each Hive. And when there are two queens – such as when a new queen hatches and the old one has not swarmed or thrown a cast, then they will fight to the death. Funny. but I find the female of the human race a bit like that. One Queen Bee per hive. Think about it!