The Purina coop with some modifications. I'm not the greatest carpenter and I made some mistakes along the way, but it was a fun build. I drew up some plans in AutoCad before I got started and have since cleaned them up some. I also have a drawing of the run/pen area and I have a spreadsheet of the parts that I used. If anyone wants them, send me a message so I can get them to you. The files are available in PDF and/or AutoCad. I am not able to upload them here. I would also be more than happy to answer any questions.