I know this article says for geese. But It can be used for all waterfowl! I mist mine more often towards the end. And as long as you keep humidity up like the article says ( I usually keep it at 55-60 )then you should be good to go! I know eggs can be a stresser but whatever questions you have...
Congratulations! Hatching baby ducks is LOTS of fun!
Also I can usually see development at day 5-6. But mine are white so I can see them early too. What color duck eggs are yours?
I am excited for this hatch along.
Also in my opinion baby ducks are much cuter then chicks!