Our chicks are raised in brooders until ten or twelve weeks, by then they are too big to fit through the 2x4 wire we use on the side walls. They can't get through the two inch top netting. When we have peahens hatching the last remaining eggs they will have some that will get out but only for the first four weeks. The lower three feet of the breeding pens is metal, so if they can fly up to the wire to get out they can get back in the same way when mom calls for them.
