Its not usually this cold here but lately its been dry, frozen and in the 20's. My 5 Rhode Island reds were loosing feather around their combs/ face so I dusted them. 2 of the girls have lost their tail feathers and were shivering when I checked on them. Is that normal or should I buy or make them chicken sweaters? They have shelter and a hen house with a heat lamp along with hay piled up for extra insulation. I feed them scratch and grain along with kitchen scraps and mealy worms for a treat.