Duck egg bad?

[football]

I have been incubating a duck egg for 3 weeks tomorrow. It has darkened through the middle, the ends are light but just the last 2 days it developed a 1X1 cm. area that is spotted (when I candle it). (rouen egg)

any advice?

 

[Goat_Walker]

Can you show us a picture? That would be most helpful

 

[football]

We waited out the time & realized that it didn't grow. That's OK though. Later I opened it up to check & nothing had grown inside...must not have been fertilized or something.