June 9th, 2011

Chicken Tractor!

last month, my dad and I collaborated on the construction of a chicken tractor. a chicken tractor is a small, mobile chicken coop, that you can move around on pasture so the birds are contained & protected from predation, but always on fresh ground. we used the design that Herrick Kimball outlines in his blog. http://thedeliberateagrarian.blogspot.com/2007/08/talkn-bout-my-chicken-tractor-part-2.html

so far, it has been working out great!

here's a shot of the whole thing:


from one end:




and the other end:


detail of the door:


detail of the vertical angle braces:


super close-up of the back wall, with pvc hoop, angle brace, and wire:


bottom corner with angle brace:



and here's the information i wish i'd had when we set out to build this thing. :)

this tractor is 3' tall at the center, and the base is 6x12. it's actually a bit longer than 12', because we put the end pieces on outside the long pieces when we built the rectangle that started the floor. if i were to do this over again, i would place the 6' pieces inside the 12' pieces in making the rectangle, ending up with a 40" center height, and a 6'4" width. that would also use the plywood sheet that the back end is made out of more efficiently, as well as increasing the height of the whole structure a bit.

to build this, first we made a rectangle out of the 2x4s, 6x12. i regret not photographing this process in order; i didn't think of it until we were pretty much done. but i'll describe, in case you want to build one. we put small blocks of scrap 2x4 in the corners, so that each screw is driven into crossgrain, not end grain, so that this thing will live longer. we did the same thing when attaching the rafter to the top of the end pieces, for the same reason; if you drive a screw or nail into end-grain, your project will crack much sooner.

having built the rectangle, we used a carpenter's square to make sure the angles were really 90 degrees, then cut and installed the horizontal angle-braces, to keep it that way and to add strength. these are cut from 1x4s. Then we cut the back out of a sheet of 1/2" plywood, and screwed it to the end. We cut the door from the remaining bit of the plywood, having measured it against the back end to get the curve right. We made uprights for the door from leftover 2x4, cut down to 2x2, and installed them on the inside of the base rectangle (because we had set ourselves up for failure if we put them on the outside -- the rafter is a 12' 2x4, and because we had put the 6' boards on the outside of the 12' boards originally, we made a 12'4" long tractor, that had to use a 12' rafter...either the ends had to suddenly bend in unnaturally, or we had to do something to compensate. the door is a little angled, but putting it inside the rectangle made a large difference in how badly it's off). we put the outward-opening door onto the uprights, with hinges on one side and a hook and eye catch on the other side. we cut four 10' lengths of 3/4" pvc down until their arc matched that of the back end, drilled 1.5" deep holes in the base for them, and installed them.

Then we had to figure out how to do the angle braces, to increase the structural rigidity of the thing so it can survive windstorms and being moved a lot. we cut them out of 1x4s, with each end at a 45 degree angle so they sit flat to the rafter & base. then we toenailed the screws into them.

having gotten all that built, we painted the whole thing with linseed oil so it can live in the sunlight without undue deterioration, then put the pvc hoops back in and covered it all with chicken wire. then we took it off those blocks and onto the ground, and moved the broiler chickens in!

we now have a tarp covering the back half, so the birds have some shade & wind-shelter, and in the event that it ever rains again, shelter from rain.

so far, i'm moving it by pushing it around one end at a time, but i intend to install wheels on the back so that it is less of a pain in the neck to move.