I know that everyone is in a different place and a different climate, but I think you may be surprised by how well your chicks might do outside. My most recent batch (silkie mixes hatched 11/19) were raised outside under a broody until age four weeks, when they came to me. They were in a cardboard box inside for maybe a week before going outside. They have done just fine with temps in the 20s, and I have been assured by some of the old timers on here that they put chicks of that age outside in even lower temperatures. Rather than focusing on building an indoor solution, it may be more viable long-term to focus your energy on finishing their coop and moving them outside.
I think Sourland just meant to ask where you intended to move the chicks when they get bigger, to see if they might be able to move in to their future home a bit early. Comments are easily misinterpreted over the internet, since you don't have tone or facial expressions as a guide, but I think everyone is trying to be helpful. I have also heard many suggestions in other threads to use refrigerator boxes, if you can get your hands on one.
