I have an 18 day old duckling that sits all the time - she sleeps through the night, is super quiet all day for the most part, and she only walks a couple of steps before she sits down. She only gets up occasionally to eat and drink and then sits again, she doesn't run around at all. I give her two table spoons of nutritional yeast flakes with a out a cup of her food that lasts her the entire day and a half, and at the moment I'm mixing chick starter crumbs with a bit of duck grower food to slowly transition her, at which point I'm hoping to introduce chick grit to her and have her eat peas at 3 weeks.