How high can raise chicken tractor be raised during transport without chickens escaping? I plan to have swivel castor wheels that fold under but when folded back will lift the tractor up. This way I can move the tractor in any direction. However I do not know what the highest clearance would still keep the chickens in when they are in the run. A 10" wheeled castor would lift it a total of 12". A 6" castor only lifts it 8". I was also thinking a loose flap of material hanging might keep them in but don't want to bother if they will stay in with these heights.