Right now I'm providing some extra warmth in my coop with a 75W bulb. But that needs to get turned off at night. I was thinking of getting an oil-filled radiator to add some warmth overnight. They are not a fire hazard as the oil is contained in a sealed unit and they provide a good amount of heat. Relatively inexpensive at around $40. I used to heat a tiled 12X16 basement bathroom to cozy with one of them. My coop is not airtight, but not drafty either so I was thinking the radiator would keep the hens (& cockerel) warm in the below zero windchills we're having this week. Is anyone using something like this?