An old women sat down in a cafe and the busy waitress came to take her order. How much is this nice a piece of cake, the old women asked? 3 Euros replied the waitress. The old women dug into her pocket and counted out her change. How much is the simplest cake? 2 euros the waitress replied. And she was getting impatient because she had many tables to serve. I will have the simple cake the old women said. And she eat her cake slowly. And then she left the café with the change on the table. She left 2 euros for the cake, and 1 euro for a tip. And when she found the tip, the waitress cried.
Why not start with an IBC and cut a hole for the door? You could build closed laying boxes into it, and something for the chickens to roost on. Put some straw or saw dust on the floor. You could add vents to the side for air. If it sat inside a chicken run that you can walk into, the chickens could be safe, dry and happy. I have an extra IBC. Maybe this could be my chicken house? I bet I could even plant the outside of it with mud and grass for extra insulation and good looks.