I was watching my chickens this afternoon and noticed 2 of my leghorns and 1 of my Auracuna's pecking at the back of my Australorp. I immediately went out and found an open wound on her back the size of a regular egg. I would appreciate any help. I did remove her from our flock of 9 hens. I read to use Hydrogen Peroxide and then Iodine tea. 7 of my hens are 5 months and 2 are 3 years old. One of the 3 year old hens can be aggressive. I'm not sure the reason for this wound. Gratefully submitted.