Extreme cold, how do keep my chickens safe?

[Abbychickenmama]

We have an arctic cold front coming into Maine for the next two days. With windchill it will feel like -45 degrees! Maine hasn’t seen this type of cold since the 70’s.
I was told to tarp the coop. Will this help? Should I be concerned? What can I do to keep my chickens safe for 48 hours? I do not have electricity available for the coop.
Picture of coop and my small flock of older hens.
Thank you.

 

[littlecoopnextdoor]

we have another couple threads going about this (I'm in the same boat!) come join if you'd like to read:

https://www.backyardchickens.com/threads/polar-vortex-prep.1561899/

and

https://www.backyardchickens.com/threads/arctic-blast-coming-any-suggestions.1561972/