This is what I do, if it helps anyone. After the first weeks, the poop and dust are just too much inside. I had an old pre-fab rabbit hutch and run that I keep under the shed by the barn. I call it the halfway house, now. I usually move them to it after 3 or 4 days. For the first couple of weeks I use the hutch only, with a heat lamp on one corner, a plate warmer near the center, and the food and water on the darker side. If temps get below 50 or so, I hang plywood on the sides to help hold temperatures. After about three weeks, I drop the ramp to the run. This gives them room to grow, and they know where the heat is if they need it. By 6 weeks, they are in the coop with no heat. I bought the hutch and run for $150, but something similar could be built cheaply