I've never grown chickens before. I bought them  last month and can't believe how fast they grow. They were fine in a cardboard box, then that was too small. Bought a plastic tub that was bigger and that worked well until this week; they are too cramped. I had an old playpen, so I set it up and put the pad in up-side-down for more stability. Now I'm concerned about whether they are warm enough. They seem to be hanging-out under the light.
They are in our "heated" garage but it isn't "toasty" in there. When the the door is opened they get a lot of cold air, if it is left open very long. But it warms-up to around 60F pretty quickly.
They have much more big feathers than they did, but is it enough to make a difference?.