I typically overwinter in 3-4 mediums and every spring the bees are in the top or second box from the top and eggs and brood are always there. I've been reversing because the bottom two boxes are usually totally empty and by putting those empties on top I believe it will slow any swarming inclination. I'd like not to do this but when I've added a super with drawn frames to the stack, the bees just expand the brood next up. this year, I've added a queen excluder to a couple just to see what happens, but I still reversed them due to fears of crowding and swarming. I would like to hear from those with more experience whether they think the bees would eventually move the brood nest down into the bottom two boxes with drawn frames. I know Mr. Bush says don't bother with reversing but it seems to me that the bees always move the brood nest up in the early spring.