Well today I made the sad discovery that I did indeed loose 1 hive this winter. I think they lost their queen sometime early in winter because when I opened the hive today there was about a cup full of bees hanging around on one side of the hive. I found 1 frame with old dead brood (about 5 bees that were about to hatch but didn't make it). I decided to shake out the survivors and let them beg their way into one of the other hives and removed their hive so they would not simply return there. I hope that was the best thing to do but they were doomed anyway...
Hate you lost them but sounds like the right decision.