You're welcome, glad you found some of that helpful! :)
I'm not sure how to visualize what you did with the bandaid, but what I used to do with lovebirds when I raised them was take a piece of soft yarn and tie each end at the bird's ankles, short enough that the legs would stay closer together...
What breed is the duckling? Additional niacin certainly won't hurt. It sounds like it has a birth defect, maybe it wasn't positioned properly in the egg. For myself, I would continue with the splints, adjusting as it grows. Their bodies are still solidifying at this age (cartilage turning to...