My cure for broodiness, which has not met with total success, has been the wire cage method. We seclude Ms. Broody into a portable chicken tractor, which has a small dog crate it in converted for use as a nest box, in the back. We leave her in the shade (it's darn hot here!) with food and water, and close up the nestbox/crate during the day. She's allowed to go in at night. Takes 3-6 days usually, and it cures the broodiness with most birds, but we have a stubborn one we're working on - silly girl has been in that chicken tractor 4 times now. I only have 3 nest boxes and 8 chickens, and can't afford for her to take up precious egg-laying real estate! Think I'll try using a mist system nearby to get her wet, maybe wet and wire bottom cage combo will break the spell....???? B/C we are not getting ANY eggs for the last several days - I think the hot weather, coupled with a snake scare 2 weeks ago, has contributed to their production shut-down.
BTW, I don't want broodies because I don't want chicks - no time or place to care for them until they're old enough.