I have a female duck who is around 6-8 weeks old. My husband found her this morning unable to walk, so we bought her into the house. I have given her a bath and when she is in the water she can swim fine and stands fine on her feet, but as soon as you take her out she can't walk. She can push up, but won't flatten out her feet - they stay sort of curled (the bath is the only place she will flatten them out). She is eating and drinking fine and seems fine in herself. I've checked her feet and it doesn't look like she has bumblefoot, but is it possible that her feet are injured or sore and that is what is causing her not to walk? She is eating and drinking fine and seems fine in herself.
Do you supplement her diet with niacin? It sounds like it could be a niacin or riboflavin deficiency. Metzer Farms has info on its blog: http://metzerfarms.blogspot.com/2011/03/are-my-ducklings-leg-problems-due-to.html. Info about riboflavin deficiency: http://wildpro.twycrosszoo.org/S/00dis/Micronutrient/Riboflavin_Deficiency.htm. Injury is possible, too, but usually there are signs like swelling at the injury site. I hope she feels better soon.
