Grew up in family that did beekeeping commercially. Late summer the workers stop feeding the drones as nectar dries up. Drones don't forage. Worker bees that fail to find nectar often have no energy to return to the hive. Drones that do return to the hive are refused food and barred from entry. Drones in the hive are pulled to the entrance. It seems brutal but there is no need for them in late summer.