During the early spring, when weather can be unstable, a cold snap can chill and kill some of the developing brood. When this happens, the bees dutifully remove the little corpses and drag them out of the hive. Sometimes the landing board at the entrance is as far as they can carry them. You may spot several dead brood at the entrance or on the ground in front of the hive. Don't be alarmed — the bees are doing their job. A few casualties during the early spring are normal.
You don't need to worry unless there are many dead bees — say, more than ten.
Sometimes beekeepers unwittingly contribute to the problem of chilled brood. You can do a few things to avoid endangering your bees:- When the temperature drops below 50 degrees F (10 degrees Celsius), keep your inspections very, very brief. A lot of heat escapes every time you open the hive, and brood can quickly become chilled and die.
- Provide adequate ventilation to avoid condensation, especially at the top and sides of the hive. The resulting icy water dripping on the comb can chill the brood.
- Inspect your bees only on days when there is little or no wind (especially during cool weather). Harsh winds will chill (and kill) brood.