In one of our double brooded national hives the queen is laying like crazy, but we have noticed something quite strange. It appears that she is filling the bottom box with just worker brood and laying a massive amount of drone brood, and some worker brood in the top box. Obviously the bees must have their reason for pulling out so much drone foundation, but it seems odd that it should only be in the top box. There is no drone brood in the bottom box. Anyone experienced anything like this before?