Broodiness is an inherited trait. That said, when you want a hen to be broody, they're not! I built a broody coop and got chicks, sure that I'd be able to put my always-broody hen to work. Of course, that's when she stopped being broody! But, with her, I think that she finally aged out of it (she's six years old now) and is fully retired from everything, including laying.