Newbie here. Of the five Red Sex Link hens we got from a farmer, one came to us looking like she'd done battle. She's missing feathers, particularly on her chest; she has a big bald spot. The appearance of her feathers has improved since we've had her these past 5 weeks, but I'm concerned that the bald spot is still bald. I'm in Pennsylvania where the winters can be very cold. Will those feathers ever grow in? Will she get frostbite? I know I sound ignorant, but I'm trying to learn. Thanks!