I usually keep a couple bales of straw on hand when winter arrives and spread some outside each coop and they seem to be much more comfortable coming out. Until I spread straw, most won't come out.
I spread some more bagged leaves in the run this morning. Also, I had 3 small grocery bags full of shredded paper, newspaper, and cardboard from the house which I dumped into the run. A couple hours later, still no chickens outside (it's 0F outside and +7F in the coop). Maybe some will come out later, I hope.