Upon examining my hive today, I noticed that the majority of the brood is in the top hive body. I've heard that to prepare for Fall, it should be as low in the hive as possible, and I'm not sure how to go about doing that. Should I use a queen excluder? It's my first year keeping bees, and I probably won't have any surplus honey, but I want to ensure their safety and warmth for the upcoming winter before I go back to school. Any information would be greatly appreciated!