There is a farm that I follow called Antiquity Oaks. A few weeks ago when I saw their blog post about their most recent chicken tractor construction, I knew I had found the design that would work!
It looks like it would be super light weight, but this thing is STURDY. So much so, I cannot move it myself. That is the down side of this for me; I thought I would be able to drag it along, but it just hasn't worked as I would have liked. I am hoping to add wheels for easier maneuvering with one person.
Other than that one con, I love this tractor! It was time consuming to build because I extra predator proofed it, but the design was very simple and it is great for all kinds of weather. I roll the tarp up during the day for more ventilation, then roll it back down at night (securing with bungy cords) for a little more security for the chickens.
I love that I am able to stand up completely in the tractor and not have to crouch all the time.
Another bonus is that when there are no birds in this in the late fall and early spring, this will double as a hoop house over the garden to prolong the growing season. Swap out the tarp for some plastic greenhouse covers and we are good to go!
The 2x4's that make up the base are 10' and 8 1/2' long. The 10' are the ones that the cattle panels are attached to at the ends. The cattle panels are only 8' 4" so the remainder of that 10' 2x4 is used to cut out a section of skid so the 2x4 doesn't catch on the grass as it drags along.
There are 2 cattle panels attached together with zip ties and then overlayed with 1" chicken wire. The front and the back each have a board attached to the cattle panels (see Antiquity Oaks' blog for pics of that) which secures the cattle panels in place so they don't sway back and forth. For the wire on the front and back I used some extra 1"x2" field fencing we had left from our garden fence and then to be extra safe (there are mink around) I overlayed that with 1" chicken wire also. I used a lot of U nails to attach all of that wire to the wood. To attach the field fencing to the hoop part of the cattle panel, I did as you would do if making a pasture fence; cut out the middle sections of the wire so there were long pieces, and then wrapped that around the cattle panel.
The door is just some extra wood I had laying around; you can make it however big you want. I forgot what the exact measurements are that I did.
The tarp I used is a 12'x16' heavy duty tarp. 16' is exactly the length of the hoop/cattle panels, so when closed at night, it goes all the way down to the bottom so no rain can get in. 12' is 4' longer than the length, so there is some overlap in the front and back to help protect against rain. The silver side is facing out; if the black side were the chickens would be way too toasty!
Are the specs clear as mud? :) If you would like to know more, send me an email and I would happy to help answer your questions if I can!