Thank you for your reply, Blue. I just candled the eggs. They are completely dark. In the past I could see the veins but now it appears the whole egg is dark and I cannot see anything anymore. Perhaps the baby duck has filled the egg completely. They seem heavier as well.
So, I will just be...
I have 10 duck eggs in the incubator. It is now day 25, I raised the humidity and stopped the turning. How many more days should I watch? This is my first time doing ducks.