At our demonstration of woodenware used in winter hive configurations, one piece of equipment drew a lot of attention: the slatted bottom board or slatted rack. The slatted rack is used for better overwintering and for swarm control. It is considered an essential hive component by some beekeepers.
The slatted rack is placed between the screened bottom board and the bottom hive body.
It provides the following:
Insulation: The air space at the bottom of the hive keeps the bees cooler in summer and warmer in winter. The brood nest is separated further from a drafty entrance and thus easier to keep warm.
Ventilation: In hot weather, bees can hang out on the slatted rack instead of filling up the spaces between the frames. They have more space to fan when it’s hot. This allows better air flow through the hive especially when used with a screened bottom board.
Protection: The solid piece of wood at the front of the rack reduces drafts at the entrance and protects the comb against robbers and wax moths. Without the rack, bees will beard on the front of the hive to help cool the hive, so the rack also affords the bees protection from dive-bombing yellow jackets.
Swarm Prevention: The slatted rack adds extra space in crowded hives and, because the bees are not as packed together, it reduces the heat in the hive. This results in a reduction of the swarming tendency.
Increased Brood Area: The queen is more likely to lay eggs all the way to the bottom of the frames in the bottom brood box, because they are further away from the light and drafts at the hive entrance.