I don't know much about duck coloring (yet). Is it like silkies, where at hatch the blues look black and the blacks look blue?
That's ok! I used to always forget to take pics too. Now that we started this thread I'm trying to take lots of pics at hatch time and after when I open the remaining eggs. It just really helps to see what's going on.

sounds like you're on the right track for figuring it out. I trace my air cells each week to make sure they look like this:
Good luck!
Oh my goodness, I'm so so sorry. That would break my heart to watch. If you hold it does it stop? I'm really feeling for you right now!

Do you have a separate hygrometer that you can calibrate in there?
Also, I found some avian liquid vitamin drops at Petco (they are similar to nutridrench). Just FYI, in case you had one of those stores close.