I want to build a daytime run as an alternative to free ranging in an unfriendly environment like this... https://www.backyardchickens.com/a/how-to-build-a-4-x-4-x-8-brood-pen I plan to build it with materials to make it lighter. I don't plan to move it with chickens inside as they will be returned to their coop at night. I would like it to be flat on the ground when not being moved. What type of wheel configurations would work well to be able to move it around a rather large property? Any help will be appreciated.