I wouldn’t worry about it too much, especially if the weather is mild. my chickens never sleep in their coop, they go up all the way to the beams at the top of the run. my vet said they like to be as high up as possible as protection from predators. I’m even getting rid of the coop because they never use it except for laying and am just building nesting boxes inside the run. maybe try building a roost or platform about 4 ft high and then have a ladder they climb to access it (my girls fly but i know not all breeds do)