I would just leave her in the open to choose where she wants to be, unless you have any particularly dominant birds that you have seen bully her in the past. Generally a broody hen will assert herself if she needs to. I used to free range my flock and never had any hens or cockerels/roosters challenge my broodies or chicks, even low ranking broodies but if the flock are penned in a small enclosure, that is when things can get a bit more aggravated. If you are able to spend time supervising their first day off the nest and monitor interaction with other hens, then I would see how it goes with her having the run of the coop. She will probably be keen to dust bath etc that sectioning off a small area usually doesn't allow.