Ok, on a different thread I posted that I have an 8 1/2 week old ducklings that has a weak" leg. He/she can walk without any problem, but for short distances, then sits down alot. If he/she is standing I've seen the leg trembling. No sign of any injury. After reading this thread I'm thinking maybe it does have a Niacin deficency though none of the other ducklings have this problem and none of our other ducks we raised ever had this problem. My question is if I give this duckling Niacin or brewers yeast do I have to seperate it from the adult ducks? Meaning will this harm them in any way? I hope I can get some answers, I don't want this duckling to be lame, and I don't want to hurt the adults either. Thanks for any help.