It would be contained in a burn barrel...was just a thought since I have an unlimited supply of wood! I think we are just going to move the coop to the south side of the house and surround it with the big round bales of hay and use a 60 watt light bulb for a few hours each morning! This is my first winter with chickens and I still have to figure out what to do with my Rooster since he is currently caged seperately!
We have a burn pile inside the horse field and one about 20 -30 feet behind the chicken coops. My coops are framed up like little houses with tin roofs, tin around the bottom and the rest is wire. They have never acted cold during the winters so I never usually worry about them or light a fire in that burn pile to help warm them. We do occasionally burn bon fires by the chicken coops though and it has never presented any issues. I do burn bon fires in my horse field on a regular basis. I guess I love my horses more LOL I make sure they are staying warm and the horses LOVE to stand by the fires.
Don't do it, it's basically pointless and (obviously) a fire/burn/smoke hazard.
It can be useful for orchards b/c only a few degrees can be crucial to avoid a frost killing all the blossoms. A few degrees is not going to make any difference to chickens.
Also your chickens will be *in the coop* on the coldest nights, yes? so they will not benefit from it anyhow.
Plus which, chickens are really pretty cold tolerant, certainly for Missouri temperatures; also, there are a whole big lotta other, much more effective, much safer, things you can do if you are concerned about their coldness.
A lot of these Big New Ideas that people get, ones that do not hinge on some new piece of just-invented technology, you have to remember there is more often than not a REASON why experienced folks do not in general do that...
I have a coop that is insulted with one inch foam board. It is not unusual to get down to 20 below in Montana. I don't suppliment heat except a heat element under the water to keep it from freezing.
The only problem I have had is a little frost bite which i now use vasaline in combs and wattles a few times a week and all is well. I also use a 2 by 4 for a perch so they can spread out there feet and sit on them to keep feet from freezing.