Hello fellow Albertan
I find it very hard to get things here in Canada like the USA can get
I tried to get the vitamin B complex for cattle and had no luck at our feed stores
If the duckling is low on niacin you can read the post
@Miss Lydia gave about deficiency’s as it gives amounts needed. I bought straight Niacin 500 mg pulls from the drug store. They come in a capsule with power. I believe it’s 1 pill per 4 gallons of water but that post will say per age / weight of duck (not flush free or time released )
I also use nutridrench, vitamin B complex and poly vi sol ( without iron ) Just a few drops on the side of the beak or add to water
The poly I got at Walmart in the kids vitamin section of pharmacy. The other two I ordered off amazon
If your duck likes scrambled eggs it’s a great way to add vitamins
Mine can’t get enough of his eggs so I know he gets his whole dose. I just take a little bit add the vitamins give that first then give him the rest of his eggs so I know he gets it