I have a 15' x 20' chicken run and I'm stumped by what kind of door I should have and how to make it fully predator proof. I have a chicken coop that will be inside the run that is 39" wide so I need it at least 39" for the option of getting it out of the run. The run will have ten 4x4 posts on the perimeter with 2x4 attached horizontally. If there's a guide on making a wooden door, that would look better. Thanks for your help! I'll be posting pictures of the completed project hopefully Sunday!