Re: 2 queens in one hive box?
You say in the past the bees have only used half of the space. I don't want to assume anything here but just guessing this was your first hive and has made it through the winter, etc. If so, you have a track record with the hive, which means that you could probably split it using the follower board and do exactly as you state. However, keep this in mind, just because 1 hive of bees act a certain way, it does not mean another will do the same. Which basically means if this new hive finds better food, etc it may outgrow their part of the hive faster and you may have to move them.
Thomas Bartram - 26 - 8 F langs, 10 Italian , 10 Russian, 6 Carniolan