Duck egg looks watery inside

[LessMore]

Hello, I have very limited experience with hatching ducks. While my daughter was watching our ducks they built a nest in the coop and started sitting on the eggs. She decided to see where this would lead. I have no idea on dates of the eggs, but they seem to develop to a point and then turn dark and when I roll them around they have a water spot that moves all around the egg when you turn it. I have discarded some of these as I'm pretty sure they were bad. I'm not sure if the rest of them will do anything and why they won't get past a certain point. Please confirm if I did the right thing getting rid of those ones.

 

[Abraeri]

Do you have a drake? If not, then they are not fertilized, which is why they are not developing. I would take one outside and open it up to see what's inside. Maybe you could post a picture?