I have four Welsh Harliquins that I hatched out from another BYC member and am very happy with then. They are approx. 6 weeks old. I noticed about two weeks ago the female not as strong as the other ones. She had previously been up to speed with her siblings till then. She does not bear her weight, waddles on the whole length of her legs, uses bill and wing tips to stay upright, and one webbed foot stays folded. I had asked around and was given the advice to try to increase intake of Niacin since ducks need more than chickens. Started them off with a game starter food then switched to flock raiser. The ducklings have had electrolyes with vitamins(including niacin) and brewers yeast in the feed now for a week. Two days ago the female's sibling started showing signs of leg weakness, shaky legs, dropped tail and difficulty supporting it's own weight. No change in the females condition. Just completed their pen with a large black poly kidney shaped pool that allows them to swim without touching the bottom. I am kind of a loose on what to do now - except being more patient. I would love to hear from anyone. I am trying to put the female in the pool as kind of a therapy. She cannot get in or out by herselp I have to pick her up. Her thighs or 'drumstick' area is, I think, very poorly developed. Any suggestions.