i got 2 nucs in early may. 1 hive has always done better than the other. shb has been somewhat of a problem, but i put bottom screens w/ pans on them. now the stronger seems to be robbing the other. it occurs between 4 and 6 pm. the weaker has a cloud of bees in what i would call the robber flight in front of their hive. the stronger is business as usual. am i looking at this wrong? if not what do i do and which do i move?