If you have a big dog cage put her in there wins she is supper broody and you know she not gonna leave her eggs, like 3-5 days to be safe. Also you don't want the eggs to get wet
If she's in the old coop leave her there. It takes about 21 days for chicks to develop then hatch. Mine sometimes kill the chicks, so I'd leave her there until the chicks can find for them self. Make sure the hen gets out to poop, eat, and drinks. You candle the eggs, use a flashlight in a dark...