I think it's important to make sure she is eating. Perhaps it is hard for her to swallow because of the bruising, but she needs to eat. To help get nutrients in her give her some Nutri-Drench, if you have that. I wouldn't keep her separate from the other chickens since there are no visible open wounds. You can put her out in the day. She hasn't been gone that long.
She is probably in a bit of shock. That will keep a chicken from eating too. If you can encourage eating and drinking with her outside, that would work best in your situation.
She is probably in a bit of shock. That will keep a chicken from eating too. If you can encourage eating and drinking with her outside, that would work best in your situation.