We have 13 hens who most are doing well. I noticed about a week ago just the Barred Rocks were picking their own feathers off of the back side. Is this normal molting? I have read lots but it seems like it could be that or something else. We are in SC and have had lots of up and downs in the weather....and it has been warmer than most winters. The Americanas, Rhode Island Reds are not molting. Thanks for any help!