I'm planning on building a brooder to raise 10 chicks in my garage until they are big enough to move into the outside coop (6 weeks) and wondering how big it needs to be? 2 sqft per bird ok? Maybe something 6' x 3' and 3' tall? Also is a wooden floor the best option for traction when the are tiny? It seems like people recommend not using shavings for the first week until the learn to eat from the feeder. Thanks for any comments.