Low low temp thermometer needed....

Is the coop hardwired or are you running cords? Have you monitored the coop temps at first light? The remote ones are cool but the batteries will freeze when it gets too cold.

I would be concerned that the eco glow won't function properly if it's not coming on until it hits negative temps. What about something like wrapping the roost with heat tape and putting it on a timer? I've got heat tape out in my pumphouse and have never had a problem with it.

 

You are also not factoring in windchill. When it was -18 what was the windchill? -50?. You are going to need the heater to kick on at a much higher temp when it's windy. Chickens are affected by windchill.

 

Actually, windchill pertains only to humans and exposed skin. Merriam-Webster "Windchill : a still-air temperature that would have the same cooling effect on exposed human flesh as a given combination of temperature and wind speed—called also chill factor, windchill factor, windchill index"

It seems that thermostats that have a set point below 0F are few and far between. You might be able to modify one to multiply or divide the signal to the relay to accommodate the need to start and stop at such low temperatures. Adding a temperature probe instead of the bi-metal strip would grant you more flexibility.

I don't live in Colorado, but the laws of physics are pretty much the same here. A 400 watt heater such as you describe would produce about the same amount of heat as 4 - 100 watt incandescent light bulbs. How much heating you would have from the 400 watts would depend greatly upon the size of the coop, its degree of air infiltration, and its insulation.

Chris

 

Tell that to my house furnace, not even in the wind. -20 no wind, house feels nice an warm, furnace not running like crazy, 0f, 30 to 40 mph wind, friggin colder and furnace running like crazy.
Chickens in coop 0f, and no wind, coop stays much warmer, than 0f and -25 windchill, it don't matter if it ain't on there skin, they be colder, and the coop be colder too.

 

I'd be more worried about any draftiness with that sort of wind/temp. combination. We were down to a windless 13° F last night and all are fine. We keep tarps on N/W sides of run fencing during the winter. A chook standing in still air at 0° F can maintain body warmth much more efficiently than one at the same temp. with a 20mph wind blowing over it. A draftless coop is probably the best way to go (baffle/cover most of door during day). We have pretty wide swings in temp during the winter and the only frostbite ever incurred was on a day that started out at 60° F and was 19° F at 4pm with a 30mph North wind (roo lost most of his comb that afternoon - rotted away for a week afterwards). Tarps to cut the direct wind and an unheated draftless coop (down to around -5° F on occasion with pretty brutal wind) with no more cold related injuries (though they spend lots of time `puffed up' to maximize insulation). The turkeys, on the other hand, have never seemed to be fazed by any of it.

Don't know of any mass marketed low temp. thermostat, if you don't mind cobbling something together with thermocouples you could make your own.

 

Maybe Merriam-Webster doesn't acknowledge that wind chill affects animals but the people that invented the concept do. http://www.crh.noaa.gov/ddc/?n=windchill

If you've ever walked out and observed your horses out in the pasture or chickens in the coop in a wind event, you know they are affected by the cooling effect the winds have in low temperatures. As Ivan illustrated, his rooster suffered from frostbite in high winds but didn't at the same temp with no winds. That's what windchill is.