I'm in the process of building a bigger coop and run. I want to move my existing flock of 7 to the larger coop and use the smaller one for three, 12 week old pullets. I plan on keeping the coops about 400 feet apart. Is it best to move the existing flock at night into their new coop and keep them locked up a few days? I'm not worried about moving the pullets into the old coop. Just the older ones. If I let the existing flock free range after being in their new coop for a week, will they return to their new coop or will they try to get into their old one?