"I'm just saying my upper entrance is 1-1/2" wide and my bees use it over the bottom entrance. I never see bees using the bottom entrance. I'm not sure if that is good or bad. I know during flow having them use the upper they have a shorter distance but, by only using the upper what is this doing to my 2 brood boxes? "
crazy, do you have an entrance reducer on? also, in the spring of the year, there will be dead bees on the bottom board possibly blocking the entrance. if you have not reversed, (i don't reverse), or cleaned off the bottom board (i don't do this until i divide), remove the e/r and carefully swipe your hive tool in to clear it.
also, are your bees in the top deep? they will utilize the upper entrance in the spring, rather than trying to take a field trip up through debris on the bottom board.