Injured Chicken

[minisambora]

One of my four chickens has been pecked by the other chicken and created a deep gash in the chicken's rear end area. So I took her out of the coop and into a holding area and the wound has started to scab over but she has lost most of her tail feathers since I put her in the holding are and she hasn't really been eating or drinking and I am worried about her, does anyone have any suggestions on what to do? Any help is greatly appreciated.

Thanks