Last summer, I had a few hens get their sides torn open by the roosters. It looked a lot worse then your hen Irish, but animal bites are way worse. Be sure to keep a very close eye on that wound for redness, heat and swelling. It may get infected.
For the torn open skin, I washed the injuries out really well, loaded them up with antibiotic ointment without the painkiller (great point BBP), put a tough pad on the wound (make sure to warm it in your hand then press & hold it on the would for a few minutes) and then wrapped them really well with vetwrap to prevent them from yanking it off. Then I put them in a cage with a towel over the top to help keep them from getting too much light to prevent them from laying eggs. I also put vitamins/electros in their water & gave them some foods high in protein & vitamin A. I always isolate my injured birds from the rest of the flock until they are completely healed. Otherwise the other birds may pick on them and slow down the healing process. The last thing a sick or injured bird needs is more stress. A warm, dark and quiet place works wonders to speed up healing.
These are the Tough Pads. I got them at Walmart. I will never be without them in my chicken first aid kit anymore. You can just leave them on until they fall off. Since a couple of my girls had such extensive damage that should have had stitches, I left them on for two weeks. Then I removed the vet wrap. The birds removed the pads in a day and the wounds were completely healed.
http://www.walmart.com/ip/Band-Aid-Tough-Pads-Hydrocolloid-Adhesive-Pads-4-count/39074951
