We use those plastic chemical containers for nest boxes, with the front cut off and a bit of a lip left. We also use plastic milk containers for water or feed, hung up with a wire hook and cut off at the front. My chooks are in a yard with breeding coops around it. The frames are started with star pickets. The front is a couple of feet of iron with mesh above this, and an iron roof. You may need a window at the back for ventilation. I prefer the less wood the better as wood collects ticks and stickfast fleas. We do have wooden perches though, a fair sized straight branch. Shelter but also ventilation is important. Depending on what chook killers you have there, you might need to cover the whole run so it is dog/hawk proof, and use strong mesh. We have pet dogs here which keep a lot of wild animals away. It is nice you are having australorps. They used to breed show australorps here.