I'm building a tractor coop for my 12 hens. As you might think, to house that many hens comfortably, It's gonna be larger than the run-o-the-mill tractor. It's finish size will be approximately 4X10. I'm going to build it solid enough that it doesn't work itself apart by constantly moving it. Can any BYC geniuses (and I mean that in the most sincere way) give or show me some ideas for wheel applications? I'm thinking some kind of assembly where I can raise and lower 2 wheels on an axle in the center of the tractor, but I'm open for any and all suggestions.