Reposting from another thread:
Okay, you need to know that when we suggest yeast, it's not baking yeast, not winemaking yeast.
It's brewer's yeast - a nutritional supplement. And generally, people use 1 tablespoon of brewer's yeast per cup of food.
I think the duckling may have a B...
It could be a niacin deficiency. I'm not an expert with ducks but I've had ducklings a few times and they always seem to have weak legs. The problem has been solved after giving them niacin for a couple of weeks if treated early enough. There are threads here on that topic and suggestions on the...