I've read that ducks need a niacin supplement...true? This is my first duck.
Ducklings require higher levels of niacin than chicks. However, whether or not you need to supplement the food is dependent on the type of food you are giving. Here is a good article that covers what you need to know http://metzerfarms.blogspot.com/2011/03/are-my-ducklings-leg-problems-due-to.html
I also recommend reading this post if you haven't already http://www.backyardchickens.com/t/750869/raising-and-caring-for-ducklings#post_10611711
I'm only asking cause the feed I've planned on feeding my ducks (Nutrena All Flock) has niacin already but I'm not seeing the amount or know if it's even enough. So my backup plan was to disolve a 500mg niacin tablet in a 5-gallon watering system.
I had one that had a deficiency. I was adding Brewers yeast to their food but she wasn't meeting her personal needs. She would lay down a lot more than the others and wouldn't walk as far. Her problem was solved in less than a week by increasing the niacin.