Rhode island red vs. Plymouth rock

[AnitaWiggins]

Air temperature or wind chill at -40F?

Both types can handle cold weather well. They key is to design your coop with good ventilation, but not not allow air to blow directly on them. Have vents above their heads where you can. Try to put the coop door away from the prevailing winds. They have very good insulation, but protection from water and direct drafts during extreme cold is the key. The good ventilation is important to protect them from water vapor accumulating and freezing on them.

Sorry to say, it's the air temperature that gets to -40 at times... It doesn't stay there long before it's back up to 0... HOWEVER, my coop will be wind proof and insulated, because if the wind gets to blowing hard enough in these cold snaps, the wind chill can reach -60F- -90F... I plan on wiring in a heat lamp that I'll only run if the weather gets to extreme temperatures to keep my chickens from freezing to death.. My coop has a great design for the summer, plenty of ventilation with windows that can be opened from the South and the East (or West of the coop, I haven't decided the direction to put my windows in yet}}.... Plenty of shade from the sun for our Summers that can get to temperatures of 100F. Our temperatures stay in the high 80's to high 90's most of the time in the summer but it can reach 100F+ at times... Door of the coop facing SOUTH instead of NORTH.. Dusk to dawn sensor opening the door to let the chickens out in the morning and closing the door in the evening.... 1/2" hardware cloth enclosing the whole coop and run, sides, tops and bottoms of the coop to make it secure... I can't let them free range, there are too many fox, owls, hawks, coons and other predators to do that...

 

[TooCheep]

Sounds like a good setup overall. My temps get into the negatives, but not that low. Two suggestions:
1- Please put your general location in your profile in the Location field. It will help people to give climate-dependent answers more easily. That location will end up displayed under your name in posts.
2- I recommend you join the Montana thread. It will be much easier to get pointers for your conditions there as well as other more local info.