Drone's are normal. They are the male bee for summer breeding.
Space in your hive is largely unrelated to the presence of drones.
A crowded hive will produce drones in anticipation of swarm division, but any hive will also produce drones. Drones will mate with a queen from any neighborhood hive, so the drones propagate the genetics of the queen in a cheap and disposable way.
If >>3/4 of your frames are fully drawn, add another box.
You might do well to purchase a short primer on honey beekeeping, you'll learn a lot.