When to put hens back outdoors

[Titania207]

Hi - I had to bring one of my girls as she had a cut and perhaps frostbite on her leg. I brought in a second hen to keep her company. They are adults, barred rocks. It’s frigid here now even for Maine these days. What temperature does it need to be before I put them out in the coop again? The house is 50-60. It’s below zero outside most nights. Will my other hens forget these rwo in two months meaning I’ll need to reintroduce them slowly? (They’ve all grown up together)

 

[nuthatched]

Put them out mid morning so they can ride out the day.