If yours are like mine, there will be a meeting in the coop the first few times it snows. This meeting will last longer than any you've attended. Then, one will draw the short straw, spend the rest of the day getting up their courage. Once the first one goes out, they will all come out.
Like Centarchid said, a little temptation will help. First time, treats and sweeping did little to motivate. I even tried taking a hen out and setting her onto the snow. She freaked out and flew back to the coop. I moved food and water into the coop after a few hours. Second time, the delay was about 4 hours. There was no third time. They all come out right away. Their feet are fine.