How long do I want for eggs under a broody hen?

[JustOneMore]

We bought fertilized eggs to go under our broody hen (no rooster). How long do we wait for them to incubate before giving up? It's now 22 days since we set them under her.

 

[draye]

Usually takes 21 days. I'd leave them for another day or two,

 

[Griffin Nest]

in the incubator it's usually 21, but with broodies they might have a long hatch, so it may take from day 21 to day 24