How long can a hen sit?

[BAMA]

I have a sitting hen that has hatched only two chicks but she is still sitting on the rest of her eggs. I know these eggs are not going to hatch as the time is way past. Would it be harmful to stick more good eggs under her? If I did would she stay on them until they hatch?
Thanks.

 

[Goose and Fig]

Nah- don't give her any more eggs. If they aren't stinky- give the eggs a few more days in case they were late additions. (unless you set them all together and know for sure) She'll probably leave them soon anyway to tend to the chicks.

You may get lots of different answers as to how long they can sit- but keep in mind that they've pretty much been fasting for 3 weeks. Their systems can get depleted if they keep it up for too long. Their "cycle" stops them from laying for some time- so they can regain their strength and rear their young.