I picked up 3 muscovies yesterday and one has a problem. He is a mature drake and in good condition but his left leg is swollen almost double.there are no scratches or abrasions, and the bones feel ok. He won't put weight on it but manages to get around. It doesn't appear broken, the joints do move (under protest). There was no pond/water for bathing at his former home but conditions seemed ok otherwise. The husband said it had been like that for 3 days but the wife said more like a week so I'm not sure how old the injury is. Is there a dietary/environmental issue that could cause these symptoms?Any help would be greatly appreciated.