While chasing a rabbit trail ... err ... chicken trail, I came across this on chicken tractors ... Wow! They're way ahead of me. It definitely solves problems with chickens. Take your pick: http://www.google.com/images?hl=en&expIds=17259,17291,17311,23756,24692,24878,24879,27400,27615,27955,28060,28156&sugexp=ldymls&xhr=t&q=chicken+tractor+plans&cp=14&qe=ImNoaWNrZW4iICJ0cmFjdCI&qesig=OVhkwspSJ0B_WBEQdlkywA&pkc=AFgZ2tnfuz1aAn7y6qAj3JnSm33OFc6F4OA_DaXqd0sjQQs-Y2jok-iS4gl3mSRVWgfM1jGGzcBfDF3Q91MlAaIQWcsSEyI_4w&safe=off&wrapid=tljp129472540159303&um=1&ie=UTF-8&source=univ&ei=IPErTZC4DcL48Abn5b3qCA&sa=X&oi=image_result_group&ct=title&resnum=2&sqi=2&ved=0CDMQsAQwAQ&biw=1268&bih=534