Because Black-Necked Swans are from South America, they are very susceptible to cold weather. They live in warm weather habitats so keeping him during cold winters indoors is great idea. Winter time and nights are the most dangerous because of the presence of predators. During winter months, predators will even access water habitats due to lack of other food sources. A swan raised by people is especially vulnerable to predators because humans obviously cannot teach the birds about wild or domestic predators.

During extremely cold weather, keep him indoors day and night. Even though there may be times during the day that you might consider letting him out because of
warmer temperatures, this may not be good for him. Going from warm to cold and vice versa can have the same effects as in humans and he could catch a cold or pneumonia. The best thing is to keep him in consistent temperatures until winter is over. You must keep him on a non-slick surface so he doesn't get bumble foot or injure his legs or feet. If you keep him indoors, he will need to be sprayed with warm water daily so he preens and maintains his feathers in a healthy manner. This watering keeps him water repellent or he can drown once returned to the pond. The Regal Swan