Hello my name is Tom I have several Muscovy ducks and I have one Muscovy duck who is two months old and he developed spraddle leg or splay leg which ever one you prefer. I did a lot of research and I did not find anyone who had the same problem with a duck of that age. I read that niacin deficiency is common in ducks, however I added niacin to the water and the duck did not improve. He spent the majority of his time hobbling on his "knees" struggling to get around. I think it was a combination of his rapid weight gain as well as the slick ground, a result of constant Georgia rain. I ended up teathering his legs together with cloth. I allowed a cue tips width to prevent cutting of circulation. Immediately after tieing his legs together the duck was able to walk, but I could tell that he depended heavily upon the leg tie. Now two weeks later I cut off the cloth and my duck is walking normally again. Just thought I'd post in case anyone ever ran into this problem as I had. Late onset splay/straddle leg.