Denise said "A half inch rock or stick stuck on one side of the outer cover. Would this not have been enough ventilation?" I would have thought that would be sufficient ventilation, but would have been certain had the rock been placed under the inner cover. Denise I recall you said the dead bees appeared wet. Back when I used to loose hives to poor ventilation, that was exactly the appearance they had. Later in the spring, blue mold would actually grow on them. How could they have become wet if not from condensation? Perhaps for some reason the hole in the inner cover did not 'work'...was not large enough to let the warm moist air escape before it condensed. I can't really speculate, except that if the bees were wet before they died, that almost surely is what killed them. Don't get me wrong, I have known bees to survive thunderstorms and rain for weeks, apparently without harm. But that is far different from a cold drip preventing them from shivering to maintain the cluster temperature. There is no potential harm to the added ventilation, no downside. At least in your climate. Try it. Lloyd Lloyd Spear, Owner of Ross Rounds, manufacturer of comb honey equipment for beekeepers and Sundance pollen traps. http://www.rossrounds.com [log in to unmask]