Hi! We have 10 hives total, 5 from April packages, and 5 from May packages, and they are going like crazy. While out the other day watching them with my trusty beagle, I noticed a bee acting funny on the grass in front of the hive. When I looked closer, I noticed she had a varroa mite on her. Eventually she kicked it off. I know its not a big deal to spot one of these things, but I was wondering whats the best way to start controlling them naturally? I know screened bottom boards are one of the ways. The thing is, is that we plan the expand greatly, so we need something cost effective. We are looking to have at least 20-30 hives going into winter. Another question is when we do split, should we put them right into deeps, or into nucs? We're not focusing on honey production this year, so its not a concern if we knock down honey production. The May 5 are on a farm and have alfalfa and soybeans to forage on, and the other 5 are right next to a commercial nursery, and crop fields. I guess my question is when is the cutoff for making splits (in southeast Michigan) to ensure that they have enough time to build up and winter properly?