I know you probably want to keep costs down so, here's what I did. I was replacing a deck so, I kept as much of the old pressure treated lumber as I could. I used this as the floor of my coop and the 4x4 posts as the corner posts. I then had a saw mill cut enough 8 ft. lumber to build an 8'x8' building. cut out 2 windows and a window in the door and covered these with 1"x1" wire. I had to buy the tin for the roof but, all together I spent $59.00........Now if you want be be elaborate, go www.poultryconnection.com find Evy Avery(goes by Evy) and click on her web-page. God and her only knows what she has spent!
