Candiebears,
If you do not want to treat your bees with chemicals, find out if the BEEK that you intend to buy from, treats their bees. If They do treat, you will need to treat for the same things they do. If they truly do not treat then you probably do not need to treat either. Bees have the genetic history to bee able handle most of the problems we have thrown at them the last ten years. We just threw a lot of problems at them in a short time and they are now just starting to find the right genetics to survive. Treating them does not help them find the right genetics.
Jim