I have an older hen who has almost stopped laying. In the last two weeks the other chickens have started pecking at her wing joints. The first joint from the tip. They have both sides bloody. I have put her in the isolation cage for now. Can I stop this? Is it because she is old? I can't think why they would live with each other for 6 months with no problem & now this. Is it time for chicken soup? In advance thanks for your help.