Combining hives is a valuable technique if the swarm season is especially busy. It's easy to accumulate a lot of small colonies which occupy many hive boxes but are unlikely to get big enough in time to produce a surplus of honey in their first year. It's really laughable easy to combine several hives once you know the secret.
If you were to just dump the two colonies into one box there would be a huge fight and you'd find a pile of dead bees in front of the hive the next day.
Place the two hives to be merged side by side if possible. Decide which of the two hives is the weaker and remove their queen. Ideally you should remove her and leave the colony without a queen for a few days to let them get the message that they are queenless.
Using plenty of smoke, remove the roof from one of the hives, preferably the one without a queen. Place a sheet of newspaper on top of the frames, make a few small holes with the corner of your hive tool and put the other hive on top of the paper without it's floor.
During the next few days the bees will eat their way through the newspaper to find their way out. By the time they have removed a substantial amount of newspaper, which you will see as woolly dust outside the entrance, they will have forgotten they weren't always sisters.
Open the hive again remove the newspaper, combine the frames which have brood, eggs, honey and pollen in one of the boxes. Try to place the frames in the manner they would be if they were just one hive, not two, recreating a regular brood nest. So place frames from the top box which have brood in between frames of brood in the bottom box, honey on the outside and empty frames beyond them.
The most difficult part of combining hives is finding the queen, If you're not able to find her by conventional means try this. Brush all the bees off a few frames, put them in an empty box and place a queen excluder on top, with another empty box on top of that. Then brush all the bees into the box and apply plenty of smoke to drive them down into the box holding the few frames.
The queen should be left on the queen excluder once all the bees have gone down below. Remove the queen, replace the frames, close up the hive and leave them to settle down for a few days before combining them.
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