I tried everything with some of my heritage breeds (ie: Buckeyes, Javas, among others) and the only thing that ever worked (and worked quite well) was to toss said broody hen (in broad daylight) into another coop....the habitants of the "other" coop were not pleased, and would continue to chase the foreign hen around, not allowing hen to settle back into a "broody stupor" in their coop.
After a day or two of this, I'd put the hen back in her own coop.
If she goes broody again, back she'd go in a strange pen.
I can do this because I have many pens, but those of you with just one pen, cannot do this.
Sure is easier than any other method to break broodies.