brooding hen, for how long?

[Lava22]

Unusual for my hen to brood but I think the harassment from the other hen keeps her in the nest box. Is it safe to give her fertilized eggs to sit on w/ hopes of them hatching? She's been brooding for 2 + weeks now...
Thanks!

 

[sourland]

Many hens will set well beyond the normal 21 day incubation period. Others will not. If the eggs are relatively inexpensive, why not give it a try?