@Stardustrose I'm not Danz but have had chickens for quite a few years & had them years ago as well. Adult hens need to have layer feed for their nutritional needs. People feed corn in the winter to help them keep warmer, but you should never feed whole corn. I feed some scratch feed along with the layer feed that has other grains in it as well as cracked corn but their main feed should be the layer feed. If she is going to be free ranging she won't need grit. You should not insulate the coop, they need air circulation to vent out moisture that collects from the droppings & just from the heat they put off. Air circulation is the most important thing. Chickens can take the cold much better than people think due to the layers of feathers they have. Just make sure to put pine shavings in the coop to absorb the moisture & keep things dry. I would not use a heat lamp either because it is a fire hazard. Many people have found out how dangerous those are after their coops burn down with the chickens in them. It sounds like your coop is small so this is even more dangerous. If you want to give extra protein in winter you can give her black oil sunflower seeds whole or you can get meal worm treats at pet stores or online. These are only treats though & should not be given as their only food. I'm sure Danz will have some other input but I hope this helps.