I have been devoring the information on this site. I'm new to chickens, have 7 different breeds raised from chicks that are now 5 months old, all hens. Igave rage 2 eggs a day right now. Today I was shocked while petting my Barred Rock she had a bald patch on her back at the top of her tail. She is the only one, her feathers are shiny, she eats well, is high up on the pecking chain. I see no signs of skin, feather or bug issues, the 6 others do not have this spot, only my barred rock. Should I be concerned or looking for other health issues? It's sad to see such a beautiful happy girl with her bald patch.