I did very well with using cochin bantams for broodies. As I can recall, I would put about 10 eggs under each. They can fluff up more than you would think, covering a good bit. There was one thing, that I will mention, although it may or may not be a problem for you.....they always went broody on the ground level. I would put little cages around them for protection and to keep the other hens away from them. That can be fine, so long as you aren't in a flood zone.