Hello - I'm hoping that someone can help ... I have 4 new ducklings (aylesburys), about 6 weeks old. All was well when I went to pick them up, but one now is struggling to walk. She is eating and drinking well, and seems lively, but just can't get herself up onto her feet. There is no sign of any injury and she doesn't appear to be in pain - no reaction from gently moving either leg, or joints. The others are fine.
I have separated her from the others, mostly so that she can get enough to eat and drink. I read somewhere that this might be a niacin deficiency, and will get hold of some niacin tomorrow to try, but wondered whether anyone else had come across anything like this.
I've had chickens and hatching eggs from the place that we bought the ducklings from, so I know that they are OK. Does anyone have any ideas?

Thank you!