I've tried a two queen colony, and I agree with M Bush. It can be a hassle. In addition, I have a theory I can't prove, other than personal experience. Big colonys are alot more defensive I don't know if it's because the population is further from the queen and pheromones, or it is just strength in numbers, but they can get downright ornery if you have anything major to do. Don't get me wrong, big strong colonys to maximize the crop is a goal we all should have. I just feel that a two queen colony, with two very prolific queens, can quickly get out of hand. I also had an issue with trying to stem the swarm impulse. They wanted to go, and did so more often than I would have liked.