I will have to take a picture later and add it. Let me start off by saying that scrap lumber is your friend. I tore down an old concession stand at a football field and have used the the scraps from it on several projects. The chicken brooder was one of them. I was going to have 100 so I wanted it to be big so I made an 8 by 8 base. I have dogs and live in the country so I also have foxes, coyotes, skunks, possums, etc so I decided to lift it up a few feet so I used a couple 4 by 4 posts cut in half as legs. I really liked not having to bend over to check on everything and it being lifted kept the critters out of it. I wanted a slanted to roof to keep rain from settling on it and had some 12 foot metal panels. I could have cut them off but I chose to keep them so I would be in shade and have a dry place to stand while reloading the feeders and waterers. I made 2 swinging doors that opened out from the center and used the cross pieces and another piece of scrap wood to lock it in. I will have to show a picture on that. It worked out well. I left an opening at the top for ventilation and then would cover the whole thing in a tarp on cool nights.
I would do a couple things differently. I would make a wire mesh floor so the droppings would go through and not become a mushy mess. I drilled holes in the bottom for drainage but it would get clogged. I added shavings but as the birds got bigger the floor sagged. I would add a drip system so I could just fill a 5 gallon bucket without having to get in there. I would also add some kind of feed drop so I didn’t have to go in and out all the time. I used 2 heat lamps and a radiant heater to keep it warm and it all worked out.