Giving your chickens a nice feeing of warm cooked oatmeal in the morning and cracked corn before bed gives them something to digest during the night keeping them warmer. And they do love these treats.
Just like humans, chickens can and do get bored and stir crazy, especially in the winter months. They love it when I hang a head of cabbage or romain lettuce on a string in the coop. They go wild pecking at it while it bobs around. It makes me feel happy that i am trying to do something for them to keep them busy.
If you are worried about your girls not having enough space in the coop, you can build a kind of cold frame or greenhouse addition to your coop, covering it in clear plastic. They will wander out into it and have a bit more space on nice days, and giving them needed time out of the coop.
In the coldest winter climates, you may find that breeds with large combs and wattles are prone to frostbite. To protect them, you can smear their combs and wattles with petroleum jelly. However, if your chickens do get frostbite, it is usually just the tips of the combs that are affected, and they don’t seem to be any worse for the wear - but it can look a little icky.
Chickens don’t like snow.Generally speaking, once temperatures are in the 20 degree F range, chickens (mine, anyway) won’t walk out onto snow. You can scatter hay or straw on the ground and this will make it more palatable for them. And I find when it’s in the low 30s, they don’t seem to mind walking on the snow as much.