Well a little more detail would be nice, but I will add my 2 cents.
If your queen dies and there are no eggs under 3-4 days old, then some of your workers will turn into laying workers. This will be noticed by multiple eggs in cells, or eggs laid in cells that are not fully drawn. It is not uncommon to see many drones going in and out of the hive, however, as this is required for natural mating. Drone brood usually forms on the bottom of brood, but is not limited to the bottom.