Many beekeepers split their hives in the spring. This is done for many reasons: 1) To create an artificial swarm to prevent swarming, 2) To increase the number of hives, 3) To create a break in the brood cycle to help control Varroa mites, 4) To encourage the bees to raise a new, young queen, 5) To make money by selling nucs or miniature hives.
There are 2 main types of splits. With the first type, finding the queen is not necessary. With the second type, you must find the queen. The most common 1st type is called a “walk-away” split. In this split you divide the hive evenly between two boxes making sure that each has an equal number of bees as well as frames of pollen, nectar, brood, and especially at least one with eggs present. One of the boxes gets left in the location of the old hive and one gets moved to a new location and some grass or other debris placed in or over the entrance to allow bees to acclimatize to the new location. Then the beekeeper “walks away” for about a week. After that time, one of the hives will have eggs and you know that’s where the queen ended up without having to find her. The other hive will have queen cells as the bees are queenless and need to make a new queen.
If you don’t want 2 full-sized hives, but still want to split your hives, you can find the queen and place her in a nuc or mini-hive (often one small box with 5 frames) with a frame or 2 of brood, food, and open comb. Since the bees cannot swarm without their queen, you have accomplished an artificial swarm. Since there is no queen laying eggs in the original hive, you have created a brood break. Since there is no queen in the original hive, the workers will raise a new, younger queen, and once they do, you no longer need the old queen as backup and can sell the nuc to other beekeepers.
More Information: https://www.honeyflow.com/blogs/beekeeping-basics/spring-split