So many of our hens have been losing feathers on their backs. At first we thought it might be mites (although we didn't see any-we are new to this) and treated them with medicated powder. Someone else told us that it could be due to our 2 roosters. Or is this just a normal moult? We don't know and we live in Michigan and we are concerned that they will freeze being so feather-sparse on their backs. Is this normal? I have read some posts that make it sound like it is....but we don't want to miss anything! Thanks for any help any of you can give me!!!!