Welcome to BYC, Ashlynne! I'm sorry you're having trouble with your ducklings.
Can you post pics and a video? Sounds like either a neurological issue or a thiamine deficiency. Are your ducks crested by chance? I had one with a thiamine deficiency once and it had similar symptoms. How old are they? Get some Durvet Vit. B Complex. It looks like this.
View attachment 2404421
That will help fix the deficiency. I like to give it to them all in their water. Put in a few squirts. For the affected ones, put it over a treat so they eat it all.
@Miss Lydia can help on actual dosages, I just guess, lol. It says injectable but use it orally. Good luck with them. Hopefully they feel better soon.