Welcome to the site. You are right about bees in our WI winters but they are tougher than you think. The big sressor comes from viruses vectored by varroa mites. Keep the mites numbers low starting about now and they can raise a healthy population of long lived winter bees. Cold itself does not kill bees. There are a large number of good beekeepers here to help out.
Welcome to Beesource!!I was trying to not use so many chemicals and treatments on my hives, and I think that approach is not working.