URGENT! Molting BR while it's -10 to -20 outside

[LaPouletteGrise]

Hi,
I have 5 chickens, 2 of them are BR that have decided to molt.
My coop in insulated but not heated.
This morning I found one of the BR dead on the floor, presumably from the -20F of the night.
The other BR seems to be cold, all huddled between two easter egger.
Should I get the BR in my basement until the temps are up a bit?
If so, how do I get her acclimated back to the cold?

Thanks a lot

 

[Eggcessive]

If I had a basement when it was 20 below, I would probably bring them all inside if possible for a short time. Put them out in the daytime if temps are better. Is your coop free of drafts while having some overhead ventilation for moisture to escape? Most chickens can withstand temperatures below zero up to a point. Twenty below is usually when people with see frostbite or other problems.