Agree with all that too. Mine are in a covered run. The ideal time for grow outs in the northwest is late summer. No heat lamp needed if timed with the hot weather getting cooler each week as the birds grow and feather out. If you can eliminate the heat source all together a variety of challenges are eliminated right off the bat. With no heat source, they need a place to “nest”, preferably a corner with hay that has sides that block draft.Oh, one thing I forgot to mention. CX can be sensitive to cold and heat, and you have to keep them dry. So when planning your growout period, bear those things in mind. If they get heat stressed too badly they can die, if they get wet and chilled by lying on the wet ground or getting rained on they can die, and if the day/night temperature fluctuation are too much they can develop ascites I think - I was reading about CX issues that can be caused by tractoring. They're more sensitive than normal chickens to weather, so I'd recommend researching that ahead of time to make sure you avoid the problems.
This is one reason I kept mine in an open air covered run with good tarp coverage - I wanted to be sure they didn't get wet. Many folks have tractored successfully, but research beforehand is recommended.