Do baby ducks need Corid?

[NatJ]

My baby ducks play in their water all the time--how do I make sure they're actually getting the Corid?

If you put Corid in their water, and make sure they have no other source of water, then any water they drink will have Corid in it.

(What dose/how much Corid to water should I use?)

I don't personally know the answer to that, but you could read the Corid package.

Or this thread might have the answer:
https://www.backyardchickens.com/threads/updated-corid-and-amprol-amprolium-dosing.818879/