I am very new to raising chickens, have 4 hens, no rooster. They started to lay eggs at 7 months. Now at 8 month my Blue Wyondotte shows bare skin on her right chest. She always was the first out to eat and the last to go inside, so she could eat. Now she hardly comes out. I thought it might be because of the cold temperatures. But now I am very concerned. Every night we have single digit temperatures and she has no feathers on her chest. Is it a desease or a behavior problem? I appreciate any help and suggestion. I already read a bunch of posts, but I am still looking for help for her. Thank you