If you don't want her to brood, put her in a wire-bottomed cage set up on saw horses or something so she gets cool air up under her. Give her food & water in there for 3 or more days. Watch her when you let her out, if she continues to act broody, put her back for a few more days.
I have a salvaged parrot cage on a stand that is used as our Broody Buster.
You could also set fertile eggs under her and let her hatch them. It's a lot of fun to watch a mama hen raise a brood of chicks. Some folks buy purebred eggs through the mail, you could also check to see if someone in your area has a roo with their hens. Mixed breed chickens are as good as purebreds except you can't show them. Otherwise, they're beautiful, healthy, good layers, and tasty.