@Mystic Vampyre It's actually 1 Tablespoon of Brewers yeast to 1 cup of feed or 125mgs of "plain" niacin to 1 gallon of water. for the first 10 weeks of their lives.
Too small a space can cause what you are seeing.Boredom. Also something about new feathers coming in, you may want to add something with some good quality protein to their feed. What are you feeding ? maybe get some dried meal worms and give them some sprinkled over their feed or offer in your hand it's a great way to get them use to eating out of your hand. When mine are growing in new feathers I also offer some high quality dog or cat kibble as a treat. Protein is what makes pretty healthy shiny feathers. Ducks are meat eaters by the way.
You say you rescued them do you know what breed of duck wild or domestic?
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