I currently have a 3x3 brooder for my 11 day old chicks. The short wall on the brooder is only 12 inches high. My girls are flying out. Really it is more like an aborted takeoff but they still clear the wall. I made the brooder out of plywood. Should I just add height to the wall? If so how much? Do I need to place a net on top? I do not know how I am going to contain these girls until they feather out. Thanks for the help.