Don't be surprised if she flaps around and knocks things over at dusk. Just leave her be unless she actually manages to get caught in the bars. She'll calm down once it's completely dark.
The holes in the bottom of the cage I used were 4x4 so I just turned it over and sat it on it's roof -- you can see in the photo that it's up on a pallet for good airflow underneath.
No, she won't like the cage at all and she will attempt to get out. She's not likely to hurt herself barring an unusual freak accident.
My broody settled down after a bit during the day, but the first night when the others were going into the coop without her she started freaking out and...