If you have a rooster you could put some fertile eggs under her and see how she does. She may give up on it in a few days, or she could continue to set for weeks. Some people will let a broody hen set for several days to make sure she doesn't quit before putting fertile eggs under her. Some hens aren't good setters and will lose interest quickly. If you want her to snap out of it and resume laying there are techniques people use to break the spell. Some put them in a small cage with no straw or other nest-type material for a few days. Some give the hen an ice-water dip. My grandmother (no joke,) used to tie a rope to a hen's leg, throw her in the pond, and retrieve her a few times to get the egg machine going again. I like the fertile egg idea better, letting her satisfy her instinct.
