we have 8 hens and a roo. have had about a year now.I noticed about 4 weeks ago that the 4 red sexlinks were loosing their feathers on their backs and you can only see small white feathers on their backs, then yesterday i noticed the bannys necks and chests are almost bald. Whats this, molt or feather plucking? At first i thought it was from the roo on the girls backs,but now that the other girls necks and chests are bald im not sure. one other thing to mention the last couple months we have had some really cold nights, down to the teens and single digits so when it gets that cold we turn on the brooder light in the hen house to keep it from getting to cold for them.Did that cause this or should we not use the light when its cold. we have had a few people tell us they dont need it, but i dont want them to be to cold.. thanks for any input.