Lloyd Spear says concerning screened btm boards:: >I don't know about "everyone", but I leave them on all year, and >personally know of two others who do likewise. Between us, many hundreds >of hives are so involved (I have 75). With temperatures of -20F, and >sometimes snow completely covering the hives, there is no noticeable >damage. All hives have generous upper entrances. Lloyd, don't you also wedge the inner cover so that the front has a 3/8" opening so that air flows through the hive? I remember you demonstrating this system at the Beekeeping Seminar held last March in Beaver, PA. Jim -- ----------------------------------------------------------- [log in to unmask] -----------------------------------------------------------