Still sitting on nest

[Quackzilla]

My broody duck pair have sat on their nest of 12 eggs for 28 days+. 2 ducklings hatched but only 1 survived. They are still sitting but spending more time in the yard and with their baby. How long should I give them with the remaining eggs?

 

[em_dawson]

None of them are pipped, correct? I might see if the ducks will let you candle them and see if you can see anything- movement, live/not, internal pips, etc. Feel free to post pics before you toss anything unless you’re positive they’re dead.