YES! You need to separate her IMMEDIATELY! A large tote, a dog kennel, pet carrier... Clean the wound up, apply neosporin or any triple antibiotic ointment that DOES NOT have pain meds in it, NO CAINE, this is very bad for chickens.
Also keep her warm and quiet. Put a towel over the pet carrier or dog kennel. Food and water in with her. Add a little poulty drench to water, or directly in her mouth for quicker absorbtion.
Chickens can recover from remarkable things. Good luck, and sorry about your girl.
Oh, keep her separate till the wound is closed up and healing. THEN you can spray it with blue kote before you re-intoduce her to the flock.