When they go broody they sit day and night leaving to grab a quick bite to eat and relieve themselves, then back to the nest. They lose weight and muscle mass. The whole process is hard on their body. To put them through that for no reason (in your case the eggs aren't going to hatch) is much worse on the bird than spending a few days in a crate with no eggs to sit on. As a side note, if she is broody and you decide to break her, put the crate in the coop. That way she doesn't have to re-integrate into the flock. That opens up a whole other set of issues.