I have bought four 12" caster wheels (two swivel and two rigid) for my 5x8 coop. I plan on placing the two swivel on the front and the two rigid on the back. If I use this arrangement, and add a tongue to the front (one of the 5' ends), will the tongue need to move horizontally to steer the coop, or will a fixed tongue work because of the swivel casters? I have a compact size tractor (30 HP) to pull the coop. Sorry if this question is already answered here, but I couldn't find the exact answer.