Need help with duck sitting on eggs

[Quackers n milk]

My duck has been sitting on eggs for 28days now none of them have hatched I am pretty sure some are fertilized but today she switched to another nest what's going on what should I do ?

 

[KingOfTheCoop02]

Sometimes they take a day or two over 28, and muscovy eggs take 35; duck x muscovy eggs take around 32.

If the duck is away for more than about half an hour, the eggs will die of cold.

Hope that helps!