One of my biggest chicken fears

My chicken friends and neighbors are impressed at how my coop is secured.  Some have called it the Fort Knox of chicken coops.  There is a reason!  One of my biggest fears with my chickens is that a predator will get in there.  I have lost one chicken to a predator, and I do not want to lose another.  I've been researching how to secure the chicken door on my new coop, and this is what I found.  I think it's a great idea!