My Finn has been on prednisone several times in the past and every time, he's had peeing accidents in his crate or in the house too. The need for more fluid plus the increase in urination AND the increase in appetite…all effects from the prednisone. Can you bring in a bowl of the snow for Sherman to satisfy him, maybe? Does he need an extra healthy treat in place of going out in the snow? maybe a Kong filled with goodies to keep him occupied for a little while will help.