Tim Peters wrote: " At our summer beekeepers' meeting it was suggested to put excluders between the entrance board and the brood chamber to keep mice out but allow the entrance to remain open for ventilation." I like the idea of a dual purpose excluder, but excluders also trap drones. They will plug up the excluder if you don't let 'em out. Gerry Visel [log in to unmask] (815) 226-6620 (815) 394-5438 or -2827 (fax)