Is the hen just staying off the nest or is she gone from the yard? I hope it's not the latter.
It's hard to say what is going on in these tiny bird brains of theirs. Sometimes they display uncanny insight & wisdom, able to discern problems inside the eggs they're setting. Other times, something just upsets the spell of their broodiness, and they'll quit right in the middle of the job.
I know some folks think you should bring broodies breakfast in bed, but I never do. I just make sure they have food & water available, whether they're confined to a cage or just in a corner of the coop. I trust them to know just how much sustenance they need, I don't think they'll let themselves starve or dehydrate. While they're just setting, they really don't need much, they're not moving around & expending much energy. They will care for their needs as well as they care for their eggs.
If you really really want these eggs to hatch then you should at least try to continue them in the incubator. Otherwise, you could bury them under a favorite bush and let the hen try again some time.