So did you get the liquid vitamin B complex? If they will take it on a tiny bite of bread you could do that. You can't overdose them so don't worry about them getting too much. I fed my ducks fermented food and I added it to that, as well as their water to make sure they were getting it ingested. I can't believe your vet would say they don't need the niacin. This stuff worked miracles for me! The hobbles are very easy to put on since the vet wrap is so flexible and sticks to itself. Just position the legs properly and wrap them a couple times. Swimming is good exercise for weak legs, but don't make them run around trying to keep up with faster ducks until they've gained strength.