Chickens normally fall sick when they have to face cold weather and moisture. So proper insulation and heating is required to keep the birds happy.
Here are some tips for winterizing your chicken coop:
1) When building a chicken house, plan for having well insulated walls. The insulation should be such that the birds cannot peck or eat them.
2) Have pine shavings on the floor and the shelves where the birds normally sleep. This will keep the birds warm and healthy.
3) You should have proper arrangements for heating the waterers so that water does not freeze. This is extremely important for having proper water supply for the birds. Alternately you may have to hand carry water buckets several times a day from your home to the coop. This can be a difficult task.
4) Anther technique that is used for winterizing the chicken coop is to have ceramic lamps for heating. These lamps just produce heat and no light. It is important to install the lamps at a height and location where no one can even touch them by mistake.
5) For certain chicken house designs you can have arrangements for having shower curtains on the outside. This will stop the cold winds and snow from making any kind of impact on the house. This technique for winterizing chicken coop may save you from having heating inside the house.