@Evadig Probably would be good for you to start your own thread and show all of the housing you have for your birds. I seriously doubt you need a heater.
Can you show your coop, inside and out, and run?
....and tell us more about your flock, numbers, ages, etc.
Will this be your first winter...
Not necessary in most climates.
Where in this world are you located?
Climate, and time of year, is almost always a factor.
Please add your general geographical location to your profile.
It's easy to do, and then it's always there!