That’s what I would like to do if this would be too cold for them
What does your coop look like? What's it made out of? Is it insulated? If it's a smaller coop it may be a better idea for a few days. I would put them in the garage as your basement may be too warm. If your coop can be closed up and winds blocked they should be okay. You may get some frostbite on comb points or even toe tips either way. Mine are locked in the shed and will stay that way until after Thursday here.
Can you post a pic of your set up. I've covered my whole run with a clear tarp. Sun shines warms area. I have a pre fab hen house. BOOO HISSSS, saves getting slammed again. Keep them DRY. Ventilate your coop. Their body temp is 106-107F. Their feathers are just like a down coat. They roost and cover their feet with their feathers. Some of them depending on breed, tuck their heads under their wing to protect combs. They will be fine. Another trick to help them with the cold is to make sure their crops are full at bedtime. I feed my a night time snack. Pellets, scratch, and mealworms. Having a full crop at night and digesting that food increases their metabolism, that "work" helps keep them warm. Some feed warm food at night time too. My chickens won't eat wet food except from beef stew, strained and then only the potatoes, carrots, and celery. They didn't eat the beef and it was tender and small pieces, crock pot stew.
It’s about 5 feet tall,made of wood, and it’s in a box shape. It’s not insulated
You could bed it well. Hay or straw along the outside wall on the prevailing winds side could offer extra protection. Bags of bedding could be used as well.
