I am having my broilers chicks arrived at late-February and I am thinking to brood them on the school farm. However, the chicken pen is outdoor, with 4-ft tall panels all around and the chicken wires to enclose the rest. I know a brooder must be warm and I will have heat lamps. But I will probably have to have a brooder inside the pen and have no idea with material would be suitable for isolation. Should I use a wooden box or a plastic box? Or other material?