I'm not going to repeat here the entire blog post where I put a bunch of photos and instructions. Suffice it to say that a Harbor Freight trailer base and a couple cattle panels makes a pretty fine mobile chicken coop.
Lessons learned: there are no precise instructions because the build depends on the trailer frame, but it's a doable weekend DIY project. Chicken wire flooring is easy to clean but isn't raccoon proof until the chicks learn to roost. Have help arching the livestock panels. Have more help when deploying the tarp. One person can easily move it by hand a short distance. Buy a trailer jack if one doesn't come with the kit. Heavy duty cable ties are a homesteader's best friend. It wasn't cheap but it wasn't ridiculous for something we will use for years at many points on our land. I went on for screenfuls on the blog if you want to know more.
Please excuse the watermark on the photo. I'm uploading the same one as on the blog. Watermarks are part of the deal in my world.