All the discussion and positive feedback about screen bottom and open bottom hives has me wondering- Has anyone tried out a long bodied hive or Top bar hive with a screened bottom.
I have on TBH that is as long as three Langstroth deep hive bodies placed side by side. Four one inch holes are placed at floor leven on each short end for enterances and ventilation.  I jokingly call it my "Coffin Hive"
 I have kept it for about three or four years, and wintering has been OK, but always a struggle.  Moisture inevitably collects on the floor, even if I tilt the hive so that it will run out the holes more quickly.  I also have had to feed dry sugar on top of the bars (Around notches cut to allow acess.)  When the bees reach the tops of the bars in January or February. (They don't move laterally when clustered in a TBH any better than than they do in a regular hive- in fact it may be even harder because the cluster cannot move over the tops of the combs, only around the sides and bottom of the combs.

All this said, do you think they would winter better if I opened the bottom of the hive up, and put 8 mesh screen over it?  These bees would be exposed to a lot more ventilation and cross drafts, because the hive is long, not tall, and <all> the combs are just over the floor.  What if I only cut out the floor under the part of the hive where the brood nest tends to be?  I would still lose most of the Varroa that drop, assuming that the varroa are concentrated in the brood area, but the hive wouldn't be quite so drafty.
My conditions:
I live in Michigan, and the Top Bar hive is in Oakland County, near Pontiac.  The field it is in is VERY windy, and gets bitterly cold in the wintertime.  Most snow blows clear from around the hives in the winter, tho the top bar hive, being on a lower stand than my Langstroths, is often completely surrounded by snow right up to the enterances. (Last bar in the back is left off in the winter, providing a one wide ventilation slot under the lids overhang.)  I have switched this year from Italians to New World Carniolans  in the hopes that they will winter better.  The Top Bar hive currently has my best Italian Queen that survived the winter from last year, but I placed a Carniolan Queen cell in the back, in the hopes of a quiet supercedure.  I have had no luck in finding the queen on may last few visits, but there are fresh eggs, and the hive is working happily, although the brood nest is still smaller than I like. (That is why I gave them the queen cell in the first place- dwindling brood nest size, even when provided with empty comb in the brood area, they just filled it in with honey.)  I suspect I have a young carniolan queen in there somewhere- but She hasn't been easy to spot!  She will likely have mated with mostly Italian Drones, since they dominate in my area.  It is too soon to tell if emerging brood is light or dark.

Please let me know what you think! (On or off list!)

Ellen Anglin