It depends on the duck...Muscovies don't have the amazing vascular system in the legs that other mallad-developed domestic breeds do. Worse, they DO share the same trait with mallards in that they don't have a lot of nerve endings in the legs and feet, so they'll walk out on the ice and snow and not realize they're freezing. Because of that they are prone to frostbite. If you have cold winters, just provide a heat lamp and don't let them out on the coldest days.
BUT if you don't plan on having Muscovies, then...nevermind. :p
I can't wait to see your ducks!