What is chilled brood? Like other beekeeping terms – the name describes the condition. When a beekeeper opens the hive to inspect, check the queen, or just to look, it prevents the nurse bees from clustering on the frame potentially causing the brood to become chilled. This can result in poorly developed bees, or even dead brood and bees. It also can be caused by pesticide poisoning that primarily kills off the adult bees, leaving a colony without the population needed to keep it warm. Another cause most wouldn’t associate with chilled brood is rapid spring buildup. The declining overwintered bee population can leave a colony without enough bees to warm the ever-growing brood nest. Regardless the time of year, the nest must be kept warm at all times (93-95 degrees). A good population of nurse bees can manage this task most all year. When inspecting your hives in cooler months – limit your hive checks to just a few minutes. Get in – Get out!