I know you are planning to free range, but that might change when there's snow on the ground. Chickens are all different, but I'll tell you from experience that my chickens refuse to go outside when it's snowing. And here in MN, that's Oct-April. That's a long time to be confined to the coop when it's tight living. Could be an invitation to feather picking. Also, poo management is tougher when the quarters are smaller as well.
You might want to consider putting plastic up on their run walls to keep the wind and snow out. Put some hay on the ground and maybe they'll be more apt to spend some more time outside when the temperatures dip.