Greetings, First of all, our family is new to chickens as of this year. We purchased them for entertainment, getting the kids to understand chores and responsibilities and oh yeah, farm fresh eggs . Below is a picture of our coop, built from pictures of the Wichita Cabin Coop. We have 6 hens, no roosters. The Chickens have been fine all summer and have loved picking in the dirt and getting used to their new home. At night they have done great climbing the ramp and roosting in the "house" portion of the coop just before dark. We had never had to shut the pull up door. However, we live in Nebraska and all the days of nice weather they were accustomed to, have all but disappeared. A week or so ago, it started getting down into the single digits and we begin locking them in at night, dropping the pop up door so that the coop would be draft free. We have their food and water in the coop with one heat lamp and an infrared red bulb. The end of October before it started getting cold we noticed that both of our Black Australorps were missing feathers just above their tails at the base of their backs. I went to our local Tractor Supply and asked them what I should do. They gave me a few pointers, like purchasing a "No Pick" lotion and making sure we have the proper feed with enough protein. The feed we have been giving them is the highest protein feed available, so I don't think that is the problem. I put the No Pick on the injured bird and removed her from the flock for a day. The area of both of the black ones continue to be bare and have gotten larger. We came home Tuesday to another bird, a Buff Orpington, that has been picked raw and bleeding in the same place just above the tail. This time, the affected area is bigger than a softball. We have now removed her from the flock and put a healing spray on the wound several times. I am just not sure what to think. I would like to get any suggestions that anyone has. I feel that the coop is big enough for only six birds, but could it be just do to the weather change? Or maybe the stress of being "cooped" up in the house portion when its so cold they don't want to come out? We leave the door open all day to the run, but they don't seem to want to come out when its cold. Our family is not home during the day and would let them free range, but we have roaming dogs in the country where we live and would probably come home to dead chickens. We do let them out as much as we can to free range, but only a few times during the week and on the weekend. Any advice/tips would be appreciated.