There's nothing wrong with keeping her in a coop or even in the house as long as she has a run and access to some grass every day (even in bad weather!) Chickens eat a lot of grass if they have the choice, and they need lots of outdoor time and sunshine. They can live quite well off of just chicken feed and whatever bugs come their way, but grass and veggie scraps from your kitchen will make them even healthier.
I have my larger chickens completely free range in my backyard. I live in the city. I think some people posting on this thread are confused about what most people mean by free range. Free range doesn't mean you let them go anywhere, it mean they are in a very large space when they can really spread out and forage. Not everybody does that, and that's fine. My chickens enjoy searching out food in the yard to much for me to keep them in a tiny coop and run, I would feel bad since I have no reason not to let them have full access to the entire fenced in yard. But most people do keep them in a smaller run, and they're fine, whatever works for you! I do keep all of my bantams in a small coop and run, but mainly for their own safety. Keeping them safe trumps their desire to run and fly around. My kids let them out sometimes by accident, but my bigger chickens are mean to them.

