bow legged duck ??

[LooseyGoosey]

I have ducklings from Cackle that are 3 weeks old. They are on flock raiser, but one of them seems to be getting bow legged.
I am guessing this is a niacin issue? What can I do about it? I don't really have any way to get anything....I have niacin tablets and vitamin b. Which do I use, and how? Online says to use however many milligrams in like one hundred pounds of food , etc. I'm not a commercial farmer obviously so what's the quickest solution here ?

 

[Amiga]

If it is plain niacin, 150 mg per gallon of water for 8 weeks.

If it is a multi-B vitamin, then base the amount off of 150 mg of B3, niacin.

That is what I would do.