Could you post a picture?
Also you need to switch them to a feed that’s suited to waterfowl babies or some kind of all flock or multiflock, look for something that’s at least 20% protein with extra niacin and other b vitamins, you can also get a b vitamin mix to supplement their feed if it doesn’t seem like enough.
Goslings and ducklings need more protein and B vitamins to develop than chicks, without either you’ll start noticing severe nuerological and developmental issues.