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If those are the extreme temperatures you can expect, you’ve got it made. Not cold enough to cause any problems and really fairly mild as long as you have good ventilation. And you can save money which is always a plus.
In that climate the only things I’d be concerned about would be rain or wind storms and predator protection. Situate it where water will drain or build the floor up by containing sand so it will really drain. Give the water a place to go when it gets wet and don’t use any bedding in the coop so it will dry. It may take a bit of thought and work to set it up right but I think you’ll really enjoy the results.
Put a solid wall on the upwind side. It really doesn’t matter that much if it is metal, wood, or plastic since it will be so well ventilated. Cover a part of the two walls with something solid that butt against this solid wall so you have created a sort of alcove that should keep the worst of the wind off the chickens when they are sleeping. I’m not concerned about the regular winds and breezes but about the storms you probably get since you are on the coast.
This “solid wall” doesn’t even have to reach the ground. All you are trying to do is keep the rain and wind off them when they are sleeping through a storm. You also need to figure out how to keep the inside of the nests dry.
Build the rest out of wire. I don’t know what stores you have in Australia, but look at your farm supply or maybe construction stores. What you are looking for is a fairly heavy gauge welded wire or something like chain link, something that can keep a dingo or whatever else you have as far as predators out. What we call chicken wire, a fairly thin gauge twisted wire, does not work all that well. Many predators can either break it or pull the twists apart.
Make it bigger than you think you need. If you are building it mainly out of wire, that should not be too expensive to do. By making it fairly large for the number of chickens you expect to have, that gives you flexibility in dealing with things that come up and you don’t have to work as hard taking care of them.
I’m envious. As long as you can come up with a location or way for it to drain, you’ve got it made. Let us know what you decide and once again,
