I just put up an extra large dog run kennel and attached it to my chicken coop. I want to divide the run in half and have separate entrances from the coop so I can separate my blue/black/splash silkies from my buff silkies. I also need the divider to either have a door or be able to step over it myself and yet keep the silkies from jumping over it. What material should I use to make this outside divider?