For two seasons I've been lifting the edge of the tractor and sliding wheels over a 1/2" bolt in order to move it. The bolts keep bending and the tractor drags in the grass. I searched and searched for other people's solutions and couldn't find one that I thought was any better. Until last week. I saw this design on another chicken forum and went to work. Chopped up a couple of old bicycles, added some reinforcing to the tractor, scrounged up some stainless table legs from the re-purpose pile and now the tractor is styling with new sporty wheels. I just have to be careful moving it with younger birds since there's about 8" of lift. Had to buy the bolts and hooks so cost was about $15. It really is a simple solution once you see it.
Lift the rear corner of the tractor and pull the handle back and hook it in place. Repeat on the opposite side. Lift the front with a rope handle and move it. Once in place, release the wheel handles from the hooks and it sits on the ground.
The pic shows it in the raised position.

Lift the rear corner of the tractor and pull the handle back and hook it in place. Repeat on the opposite side. Lift the front with a rope handle and move it. Once in place, release the wheel handles from the hooks and it sits on the ground.
The pic shows it in the raised position.