It's funny. We have this RAGING debate in these parts about SBB and whether to leave them open or close them up each winter. Sometimes it get pretty ugly.
I'm of the school that says SBB are great for summer ventilation and varroa control, but I like to close them off for the winter, to basically do what the slatted rack is supposed to do--keep the brood area warmer going into late spring.
But there are others who swear on their mother's grave that they closed off the SBB and the bees all died, how leaving them open makes for healthier bees in the winter, how you don't have to close it off because the bees don't heat that area beyond the cluster, blah, blah, blah. (You can tell I'm biased).
Then we have the solid bottom board folks who don't say a thing. They just sit on the sidelines and watch the rest of us argue.
I've never felt, if you have a solid bottom board or if you close off the SBB, that a slatted rack really helped, particularly if you are using an entrance reducer. Some of the old timers I talk with never believed the claims either. I own two used ones. Maybe it's time for a little experiment.
Grant
Jackson, MO