Finished my chicken tractor today, but cannont figure out how to put the wheels on. I am thinking that retractable wheels are the best choice, but can't find any and not smart effough to make myself. My question is this, if I put 4 wheels on this thing, it is going to raise the tractor off the ground a few inches, will this be a problem with predators. Keep in mind I do have a secure coop attached to the tractor to put the birds in a night. Any help is appreciated.