We have three adult Khaki Campbell duck hens. One is about two years old, the others one year old. We had a friend tell us to make sure they have extra Niacin, so we always gave them a vitamin supplement along with their feed. We have never had any problems with their feet. In March, we brought home seven ducklings. (That sounds like a lot, but we have a small farm with a pond near the house.) I don't know how old they were, but they were getting gangly, and the feed store wanted to get rid of them. it turned out that four of them were Muscovies and three were Pekins. So, we took them home and put them in a nice hen house by themselves with a penned in area until they were old enough to go back and forth to the pond. We trained them to walk to the pond. Now they are able to free roam (with available shelter). They do interact some with the Khakis, but mostly the seven of them stick together, Muscovies and Pekins alike. Ever since we brought them home, we have given them the Niacin supplement. So, here is my question. The Pekins have turned out to have perfect feet, yet all of the Muscovies have turned in feet, some worse than others. We even added extra vitamins as we noticed this happening. They seem to be able to walk around and swim okay, but I am wondering if someone has any advice or explanation that could help treat them or prevent this in the future. Thanks for any help!