"did you notice any difference in hive size between your open and closed bottom board hives?"
Not too much difference. I had two really good hives that did really well, one was an sbb hive an the other was an upper entrance hive. I did notice that the bees didnt much like to build on the very bottom of the bottom frames right next to the screen. Also, the winter cluster is much higher in the SBB hives than in the UE hives.
"Has anyone else out there noticed increased moisture in open screened bottom board hives?"
As I stated, one of my SBB hives was having a serious condensation problem to the point of mould, but I propped up the lid about 1/4 inch and it went away.
Southern Oregon Apiaries
Thanks Sol for the information, our hives that are SBB's appear very strong as we went into the fall. We've had a couple days of flying weather recently and 80% of our hives seem strong. Maybe we'll know more in the spring concerning ventilation differences up here in the snow country. At this point in time I would say our weak hives appear to be from bad laying queens of which we had many and some we didn't get replaced. Thanks!