Here is one I built for the Bantam Golden Seabrights.
It works by pushing down the handles and latching, then it balances over the tires. Made with bed angle iron and other scrap parts. This is the one I gave away to a friend. Wish I had taken a few pix of if finished.
My chicken tractor is my profile image. Will edit this in a few when I get home to add video.
Play list of my Chicken tractor. Made of 95% scrap. Took a while to collect it all and took a bit of time to utilize every part in the best way and fitment...