I think we are still waiting on your photos?
One eye closed and swollen - general care is to flush the eye with saline, see if there's debris, pus or injury. Remove any pus or debris, then apply an eye ointment.
Isolating would indicate she's not feeling well, but a bird at the bottom of the pecking order may also be avoiding bullies if she's not able to see well with one eye closed.
If you need to, cage her within the run/coop and provide her with her own food/water. Monitor to see that she's eating/drinking, that her crop is emptying, that she's pooping and has no lice/mites. Also listen to hear to make sure there's no indication of respiratory disease like coughing, sneezing, rales, wheezing, etc.