I'm thinking of building some breeding pens and i think a hoop style would work best for me.does anyone have any pictures of any maybe ones that are movable? I'm thinking around 8'-10' long or so? maybe made of pvc pipe for the hoops with 2x4's around the bottom and tarps for the tops.what would work good for the backs and the front for a door to gather eggs,feeding and watering.Thanks!