This is our first year beekeeping, have 4 hives. One is a very late bloomer, only about 2/3rds as many bees as the other 3. I have been noticing alot of yellow jackets (YJ) coming in and out of the hive. Last time I smoked hive for opening, probably 50 YJ made a hasty exit. I opened things up and did not see any evidence of a YJ nest starting. I put in an entrance reducer to 4.5" X 3/8" and watched the bees better controlling access, but don't want to slow the bees in their hive buildup which I believe is critical to their survival in the Upper Peninsula winter. Comments?