From hatch. lol actually any of us that feed our ducklings chick starter or feed for chickens should supplement with a form of niacin. I rec Nutritional yeast and with that many youngins to feed I'd buy bulk lol Water fowl need more niacin than is found in feed for chickens if they don't get it some can end up with lameness and neurological issues but it is usually leg problems more than neurological unless you have crested. So putting 1 Tab of NY into each cup of feed you serve should be enough Do you own a hatchery? I haven't seen many members with that many ducks. Can you tell us about your birds and how you take care of so many I have a total of 42 and to me that's a lot. lol I am always interested in why members got into ducks/poultry and how they keep them.