For just keeping hawks out, that would probably work. For anything else, it wouldn't work at all.
I would worry about the snow load in winter, as those small holes will catch snow and you'll end up with a heavy blanket of snow that will collapse it. I would go with something that has larger holes, that will let snow through.
You don't normally have to worry about chickens being killed by something reaching through the wire ceiling of a daytime walk-in run, it's more of an issue on the sides. So, you only need openings in the wire that are small enough to prevent the particular predator's body from going through. Now, if your run is only 2' high, then you need the same security that you need for the run walls.
I would worry about the snow load in winter, as those small holes will catch snow and you'll end up with a heavy blanket of snow that will collapse it. I would go with something that has larger holes, that will let snow through.
You don't normally have to worry about chickens being killed by something reaching through the wire ceiling of a daytime walk-in run, it's more of an issue on the sides. So, you only need openings in the wire that are small enough to prevent the particular predator's body from going through. Now, if your run is only 2' high, then you need the same security that you need for the run walls.