This looks a lot like our tractor. So many of our neighbors out here in the wilderness have given up on chickens due to predators that we decided to predator proof obsessively. Here's what we've done, in case any of it is helpful. A caveat is we're new to chickens, too, though this means we're fresh off a ton of research.
Firstly, everybody told us to be sure the bottom of the coop was wired somehow. Friends of friends were texting about this out of the blue, so that apron sounds like a very good idea.
This next part may seem excessive: our tractor sits behind a 6' welded wire fence with 6K volt electric wiring to discourage bears, mountain lions, coyotes, foxes, skunks, opossums, raccoons, bobcats, mountain lions, domestic dogs and cats, Chupacabra, Voldemort, etc...from gaining direct access to the tractor. Trees around the run have been trimmed to make it harder to jump in from above.
Again, we're in the wild. We see these animals on our cameras monthly, if not weekly, except the mountain lion, which we saw in person a mile away

Our chicks are 10 weeks old, but when they're bigger, the electrified yard will be their run when we can't supervise. Right now, because hawks have been picking off a neighbor's smaller hens, our chicks stay in the tractor unless they're supervised. We're installing measures for aerial predators that are probably not germane here.
The tractor's run and windows are covered with 1/2" hardware cloth like yours, and to discourage rats & weasels (a neighbor lost an entire flock to the latter in a night), I filled any gaps over 1/2" with sprayfoam, like the spaces under the roof metal. **It's important to do this when the chickens aren't around because foam's so messy, and you know how fast chickens swoop in for a taste-test. Sprayfoam isn't impervious but is supposedly effective at discouraging attacks.
We see families of as many as 5 raccoons at a time, so in case any are wiley enough to get into the run, I added keyed hasp locks to the doors.
After all this, we realized we'll have a bigger flock than our tractor will accommodate, so we just ordered a Quaker-style coop and will move the teenaged chickens to that before moving the new babies to the tractor until they're big enough to move in with the older flock. Chicken fever in full effect.