Another believer in the slatted rack just join the ranks. After weeks of watching my girls beard up the front of the hives after their long day on the job, I installed my racks last weekend and noticed the results tonite. More than half of the beard is gone in all 3 hives. Soon it will be time to try the rack as a Queen excluder, but there will be some modifications to them to work properly, way too much space on the underside. :D