It is a good article. I have had coyotes in the pat both dig under a fence and go over a fence. I had a bobcat dig under a fence and killed 14 birds. It made the mistake of coming back a couple of nights later. I have had a possum dig under a fence and kill a bird which I also caught in the act. This is what I use on my gates and so far have had no issues. Maybe the coons are as smart here as they are in other places.Raccoons are pretty good at getting latches open. But I believe it is something like as long as they are 3 steps to them that they can't get in. Here is an infographic though which better helps answer that question for you - http://www.poultrydvm.com/featured-infographic/tips-for-protecting-poultry-from-predators