We have a "weeble-wobble" duckie too. Ours is a crested and that causes her issues. We have to add niacin to her food. I am not familiar with dumor brand as we haven't used it so I can't speak on its contents but I wouldn't think extra niacin would hurt. For ours though we bring her inside at night, give her some extra time to eat undisturbed (she gets cucumber, canned chicken/tuna, tomato and food mix), and then she sleeps in a crate (again so she is undisturbed by the others). The next day she seems to do better, more steady on her feet. You could try something similar to see if it helps her. Also watch her to make sure she she is not getting into something she should not. Good luckI have 3 Pekins about 7 weeks old and 1 of them seems to have weaker legs than the others. she always falls down when she runs or jumps out of the pool or of the step of the back deck where they like to sleep. I have feed all nine of my ducks the same using dumor chick starter/grower which I heard has the appropriate amount of niacin for growing ducklings. Should I add more niacin to their diet or could she have another problem?