It's not cold until it's below freezing

Rhode Island Reds outside scratching for bugs

During cold freezing weather, egg production and hen comfort will be increased if they have plenty of (non-frozen) water to drink. If you don't have piped water to the hen house, I recommend using 10 qt. galvanized buckets as water'ers. Fill them with warm water and take them out to the hens. Take the frozen buckets from last time back indoors with you. Galvanized buckets are good because plastic buckets split when they freeze and poultry fountains are hard to open when they're partly frozen. Rubber buckets and pans are also good. You can place a tennis ball in the water'er and when the water freezes grab the ball and it will pull the ice sheet off with it.

 Chickens can handle very cold temperatures. Some experts say chickens don’t really start suffering until the temperature inside their coop falls to minus 20 degrees Fahrenheit. They’ll start suffering earlier if it’s damp inside the chicken house, or if they haven’t adapted to the cold, that's why its not a good idea to heat the hen house.  The hens will be warmer during the day if they exercise. They'll be warmer at night if they go to bed with a crop full of grain. The two can be combined by putting a thick layer of loose hay or straw in their pen and scattering a light feeding of grain in the morning and a heavy feeding of grain in the afternoon. Around the turn of the century it was common to have a "scratching shed" attached to the hen house, which was a substitute for range during the winter. The scratching shed was usually open-fronted (that is, walled on three sides only, with chicken wire on the fourth side), with a thick layer of loose straw on the floor. Grain is fed in the scratching shed, which is where the birds get their fresh air, exercise, and sunshine. Always make sure that the girls have a full crop of grain and other nourishment before roosting at night. Birds with existing health problems such as injuries or illnesses or younger less feathered birds may need to be put in different housing arrangements so that they will stay warmer.