I have acquired various assemblies in my collection of hive stands and wonder if anyone can provide insight into the

proper usage. Specifically how the bottom board comes into play.

I overwintered my colonies in a shed with one open window, and winter here is about -10C for about a week.

One hive stand has fixed wire mesh and a sliding mite board,

the other is a steel frame with wheels and open center, the last one has an enclosed base. I noticed that hive with the enclosed base is very vigorous. As for my other two, one is less vigorous and the other died:(.

Also an aside, the population of the deadout was low, but some bees and pollen seem to have molded over. Is this chalkbrood, and what should be done with those frames(plastic) before reusing?

Other factors such as their positions in the shed and hornet/mice/ant/spider assaults may also have effected my results.

Summarily, is it correct procedure to have an open center in the summer and a closed one in winter? At what dates should the bottom be closed/opened/