Help!! Injured hen not getting better! Deep neck wound into fat.

My hen has a large wound on the back of her neck aprox 2x2 the top is scabbed over but the bottom half if into the fat layer. I have been examining it daily for 5 days since the injury and keeping it clean but there is no visual change. My husband wants to kill her, but she seems fine. She is active and eating and really doesn't even mind much when I examine the wound. Any advice would be helpful. Thank you for your time. We are new to chickens.