Australian Black Swans are southern hemisphere species and cannot tolerate very cold weather. She needs to be brought in for the winter. Yes, you need to switch her to a mixture of cracked corn and poultry lawyer pellets. Provide her with lettuce to help her vegetative needs during the winter. There is no guarantee that the swan will take another mate. You will need to prepare a pen, enclosed top to bottom to protect from predators, 1/2 in water and 1/2 on land with zero entrance. The new swan will need to be kept in the pen for approximately 2 weeks to ensure no aggressive behavior between the two. A boat or other rescue equipment should be kept ready in the event one becomes aggressive when you place the new swan onto the pond after 2 weeks. The pen should also have a feeder enclosed. Do not get another swan until the weather permanently warms.

Even if you do not get another swan, the remaining swan will be just fine. You might just add some ducks and geese to the pond and the swan will get along fine. Finally, should you need veterinary or other such assistance, you might contact Wendy Hermon at Swan Support in Windsor England as she can further advise as she has experience with Black Swan needs. The Regal Swan