Poultry and other captive fowl may get this syndrome which causes the toes to curl under or overlap. In the case of the swan, the toe probably appears to curl under the webbing. Most lameness issues such as curled toe result from a dietary deficiency such as Riboflavin. Please take the cygnet to a waterfowl/avian veterinarian with experience in this condition for treatment. If the condition has progressed beyond treatment, you may need to keep the claw trimmed back so that it does not tear the webbing. The cygnet should do fine, but veterinary care is critical. The Regal Swan