Hi, first time chick parent here. Got my 20 new chicks yesterday, put them in a brooder that was too small. So today I made a much larger one and moved them over. Then I just watched. They would take turns running, i mean running as fast as they could go, back and forth and back and forth. Nothing was scaring them, so I am assuming this was normal behavior? Is this how they "play"? Also, when should I worry about them starting to fly up a bit in their brooder? They are 3-4 days old. Thanks!