First time broody
If she is separated from the others with food and water at her disposal she should do her thing and be fine. That will also mean the other hens don't add to her clutch of eggs. You may have to take her off her nest once a day to make her have a break (I've found I've had to do that with our little bantams that we moved indoors to brood). If she's been sitting for 8 days she's committed and won't easily be put off sitting on her eggs and some hens will dehydrate/starve themselves to death sitting, so make her take a break.
Hatching under broodies is a lot of fun and it's lovely to watch the mother chicken teaching her babies what to eat, how to scratch, how to catch bugs, how to perch, and they are adorable when they are snuggled up together (especially when they are really little and you see little heads poking out from under the Mummy chicken's feathers).