Most of my hives seem to have wintered well but in two of them I found no queen,no eggs and no brood. I know my guess is something happened to the queens or they've swarmed already what are your thoughts? I did find a queen cell in one of them that appeared to have hatched (nicely cut out on the bottom). I put a frame of unsealed brood with eggs in each hive. My queens are clipped and marked at least they were last fall.