We have a pair of mute swans approximately 6 years old on a lake in Missouri. We have a fountain to keep water open during the winter months, but I am wondering if we need to build some type of shelter for them. If so what type, a lean too with one side open or ? Any suggestions ? Last year we had a pair that seem to freeze to death, it was too sad to watch again. Appreciate your help in caring for them through our winter.