Yes, you should do all of the above. Breaking the ice would be a good solution if the pond is very small as the swans will still wander and can either get trapped on the ice farther on the pond or fall through and can't get back out. Another problem is that predators such as coyotes, bobcats, etc., will use the ice as an opportunistic time to go onto the ice and capture a swan that is trapped on or under the ice. So, this is not a real good solution.

Yes, swans must be fed all of the time. Use 1/2 mixture of cracked corn and 1/2 mixture of poultry layer pellets to supplement the swans' diet. You can also feed them a little bread and plenty of lettuce as a treat to supplement their need for grazing grasses and aquatic vegetation. Ideally, there should be an aerator or fountain on the pond to insure adequate oxgenation so that the swans and other birds do not die from botulism poisoning.

Yes, the best solution for the winter is to place the swans indoors during the nighttime or other very inclement weather during the winter months. Extreme cold or blizzard like winds can be fatal to a captive swan as they cannot flee to shelter themselves (i.e., migrate). The enclosure in the barn still needs to have adequate protection from predators (i.e. appropriate enclosure so that a predator cannot dig under or climb over the enclosure to attack the swans) and the swans cannot roam freely throughout the barn and get injured. The indoor enclosure must have a food pan or bucket with the above mentioned dietary supplements for overnight. Caution must be taken so that the food is not attracting rats, ants and other pests. The food needs to be changed daily and should be placed in a bowl and fully submerged in water. The swans need to have water to eat so they do not choke on their food.

Training the birds to come indoors at night will take a little time, but eventually, they will understand that when the boat is placed in the water, it means that it is time to go indoors for the night. They may even be trained without having to use a boat. The Regal Swan