This goose is not likely to fly like an Egyptian
Polydactyly seems not such a rarity compared to polymelia; nevertheless, here is a case of a third wing.
An exotic goose, identified as Egyptian Goose (Alopochen aegyptiacus), with an extra wing was found struggling on a golf course in Hollywood, Florida.
The condition rendered the goose unable to fly or even walk without dragging what seemed to be a third wing. The polymelia was corrected surgically by veterinarians at the SPCA Wildlife Care Center in Fort Lauderdale, who removed the extraneous growth.
Currently, the patient is being monitored in order to verify that subsequent surgery is not required for the goose to tuck in the wing during cursorial locomotion. Flight is not in the prognosis of this goose, even post-operatively, but rehabilitators hope that the goose can live comfortably in captivity.
There is a video supplement to the story.
Thanks to G.B. who circulated the news on the ASA Yahoo! group