If the swan is able to fly, then there is a possibility that the swan's wing is injured or it got into some substance that has caused the bird to keep its feathers healthy. The swan needs to bathe or have someone bathe it to get the substance off the feathers. If injury or substance is the cause, the bird needs to be captured and examined by a veterinarian experienced in waterfowl/swans.

If the swan cannot fly, then there is a possibility it has a condition known as "angel wing", "slipped wing", "backwards wing", etc. Angel wing is caused by two issues: The bird has too much protein in its diet, especially at a young age. The wings develop too fast and much quicker than the supporting wing tissues, i.e., tendons, muscles and other soft tissue. Without the structural support of the soft tissues, the wing slips out of its normal position and then appears to have ruffled feathers and dragging out of position.

The second issue is a birth defect in that some genetic anomaly causes the wing to develop abnormally and the supporting tissue and wings have something anatomically wrong with them. If you can send us a photo, we might be able to better determine the cause. The Regal Swan