Just make sure you secure the dog house really well. We had our Pekin ducks in one, with a thick door made of 2x4s on it, though the door was just held up against the house with another 2x4 wedged into the dirt. We thought it was secure enough, but... One morning we went out, the bottom of the door was pulled out all of like 3" and something had dragged off our drake we'd raised from a baby.
I guess the predator was strong enough to pull the bottom of the door away just enough to grab the duck and drag it through. Our other duck was at the back of the doghouse, so was safe. I found the victim about 100 yards away, picked clean, only the wings, neck, and backbone left. (Sorry for the graphic description, some people want to know.)
That should be lots of fun with a broody hen. We're hoping to have some of ours go broody sometime.