I think Waddles my Khaki Campbell had a niacin problem forgot the full word, I got him from the feed store came home and saw that his foot was sort of bleeding, and it was swollen. about a week later his foot was gone, now he walks on the lil nub, I call him pegleg at times cause he reminds me of a pirate when he walks, I want to figure out how to make him a little show or little foot thing to put there, seems painful walking on the gravel and brick. He also has problem getting into the swimming pool so I got to corner him to catch him to be able to place him there. Seems like a very happy duck very sweet one, loves his neck rubs lol. I do not think he will be able to fly though