Oh my gosh, I hope I didn't make you feel ignorant!! That wasn't my intent at all and I sincerely apologize!! Every one of us has made concessions between what we would really want and what we can afford, as well as what our building skills can handle. In my case, that was a lot of concessions!I don't have any underground protection and I know I need a better door, but (you can't tell from the photos) I do have metal hardware cloth covering the fences. I don't know where to get a good door or fence though because I bought that one at Lowes because it was the only one that was the right length. Also how exactly do you install underground protection? I'm very sorry I probably sound so ignorant and my run probably looks so awful, but it was the most affordable and nothing has happened until now, so I didn't think it was so urgent, but I see your point and I will fix it as soon as possible.
Edited for grammar
You don't really need to spend money on a new door! Just get some wood and attach it to the outer parts of the frame, there where the big gap is right between the frame and the side fencing. If your door opens in, attach them on the outside so they don't interfere with the movement of the door. If the door swings out, then attach them on the inside. That seals up that gap! As far as underground protection goes, if you run some fencing - almost anything from welded wire to chicken wire to hardware cloth will do - lay it flat extending outwards about 2 feet and then fold it up and attach it to the chain link, you've just put in a barrier than predators can't dig under. They have the sense to find areas where we forget protection, but if they decide to dig for a chicken dinner they always start as close to the fence as possible - they don't have enough sense to start digging 2 feet out. So they start to dig and hit the protection hidden there.
Lots of folks actually dig a trench and bury fencing underground so predators hit it when they dig, but my ground was too hard and way too rocky for that, so I just used hardware cloth and did exactly as I suggested. I ran hardware cloth up about 2 feet on my run fencing, folded it at the bottom and ran it out about 2 more feet out, pinning it to the ground with landscape fabric staples. The grass grows up through it so we can mow right over it. And it works! Our English Setter, Molly, wanted to get in at the chickens so badly when we first put them out. She ran the length of the run a few times and when she couldn't find a way in she decided to dig underneath. She broke and bloodied a toenail and decided they just weren't worth that kind of pain!
Rather than being criticized, you should be commended for wanting to deal with that pesky raptor as soon as you spotted him. The rest will come as you can get to it. And I need to learn to phrase my responses in a more kindly way!