Yes, the swans do moult, but this sounds not only a little late, but even a bit more strange as the moult usually does not leave the wings completely devoid of feathers.

Are the feathers pink in color by any chance? If so, we have been researching this phenomenon in swans and if it is bacterial in nature, the swan can die without the ability to keep itself warm or water repellent.

Since Trumpeter Swans are protected throughout most of North America, we would strongly suggest calling your local Wildlife Rehabilitation Center, Fish & Game or the North American Trumpeter Society to see if they can intervene and work with the bird until it grows back its feathers. Then, it may be released back into the wild once winter has passed.

If you have a photo, we would love to see it and use it for our records of various wing and feather anomalies. Please let us know if we can use the photo with your permission. You can forward the photo to this site's webmaster along with the permission and the webmaster will get it to us. Thanks so much. The Regal Swan