This is why it's sooooo important to do your homework before getting any kind of animal! You said that you asked a bunch of people and they all told you that 1) ducks and chickens eat the same thing, and 2) they can be kept together without any problems at all. I don't know the types of people you hang around with, but they don't know their bum from their elbow when it comes to raising ducks!
Ducks and chickens can get along, but they need to be kept in different pens, unless you want to make your chicken coop as filthy as possible and risk your chickens getting foot rot from constantly walking on wet, feces-laden ground. Also, chickens have a pecking order, and so many ducks get injured by being constantly pecked by their sharp little beaks, and when they're all locked in the same pen they have nowhere to go in order to escape!
I'm surprised there are no 24 hour drugstores where you live, most of those carry all kinds of vitamins and you'd be able to find niacin or B-complex pills easy peasy. Please go get it FIRST THING in the morning, your little ducky baby needs you!
