I just put together a two-queen hive with my warre setup using two cast swarms that I caught in the last 2-3 weeks. It will be my first attempt with a 2-queen hive, and it's an interesting endeavor so I wanted to share my process.
The two swarms involved were fairly small and caught a little later than the big primary swarms in late april/early may, so I'm assuming they're cast swarms with virgin queens (one was caught on a swarm call and one was from a swarm trap). I've been reading some interesting information on making 2-queen colonies with weaker over-wintered hives and they become equally or more productive than strong single colonies, so I thought this strategy might help small cast swarms build up quickly for winter. I am not expecting to harvest from them, just seeing how quickly they can build stores.
The two swarms began in separate boxes, one (from a swarm call) had 7 frames partially built and the other (bait hive) had 6 frames partially built. All had a good mix of brood/larva/eggs.
The 2-queen setup has 2 boxes for the brood chamber, vertically divided into a 4-over-4 arrangement.
I made vertical dividers for each of the two boxes that occupy the brood chamber, thus keeping the queens separated. Also the bottom board has a solid partition down the middle. The goal is to have the two queens completely separated.
I put the swarms into their respective halves over the two boxes. On top of this divided 2-queen brood chamber is a queen excluder, over which is an empty super. The workers can mingle in the super and work together to create stores. I put 'ladders' made of foundation in the empty spaces of the brood chamber, as well as in the super, so they can move easily up and down.
Every couple of weeks I will take a frame of capped brood from each brood chamber and put it in a spot right above the excluder, giving the queens more room to lay in the brood chamber and at the same time helping the colonies rapidly expand (and hopefully reducing swarming tendencies).
If all goes according to plan, the two queens will rapidly expand the colony and the workers will quickly build and fill the supers. From there, at the end of summer I will either: (1) divide the super, remove the excluder and overwinter 2 side-by-side 'nucs' or (2) pull the dividers, let the queens duke it out and overwinter a strong colony.
I will try to update every few weeks with progress compared to my other strong swarms and over-wintered colonies. It would be cool to have a system to productively manage and expand these traditionally smaller and less-productive secondary swarms that sometimes aren't considered as valuable.