Swans will use an indoor shelter as long as it is big enough for them to walk around, has protection from predators (meaning completely enclosed such as a barn or garage, straw or other soft non-abrasive flooring and the capability of having a food and water dish free from pests such as ants, rats, etc.

Again, a garage or other such indoor structure would work. The ideal situation is to train the swans to go outside during the daytime and to go into the structure at night. If there are days that are really cold and blistery, the swans can stay indoors until the weather improves.

The major problems with keeping swans on a lake or pond that can freeze is the swans can drown, have no food or water source and predators can access the ice to get to the swans.
Predators are especially active at night and during the winter months. Swans should stay in the middle of the pond at night to protect themselves from predators, but not all swans do this and fall prey to the animals. Additionally, your small pond will be harder for the birds to seek shelter in the middle of the pond, especially if it freezes.

You need an aerator/de-icer to keep the pond from freezing, even if you only allow the swans on the pond during the winter months during daylight hours (1 hour after sunrise and 1 hour before sunset when predators are active).

We can refer you to Sue Cruz Vertex Water Features at (800-432-4302) to help you with your aeration needs. You will need an aerator even during the summer months to keep the swans safe from botulism outbreaks which can occur when oxygen levels are diminished in ponds and lakes. Aerators keep the pond and the swans healthy.

If you can use both of these systems, an indoor structure at night and an aerator to keep the pond from freezing and allow the swans to enjoy the pond during the daytime and stay indoors at night, they will do just fine. The Regal Swan