Hardware cloth is called that, because it's made like a woven cloth. The wire weaves over and under, like the threads in a cotton cloth, except the space between the wires is larger. The size of those spaces can vary, depending on what you want to buy, like 1/4" or 1/2". It kind of looks like a large, heavy duty screen. Only it screens out animals, instead of bugs.
When I use hardware cloth, I usually use the 1/2" size. Around here, it's made with a thicker gauge wire than the 1/4", so is stronger. 1/2" will keep out rats and the smallest species of weasel. 1/4" is needed to keep out mice. I use it over all the coop openings like windows and vents. It makes an excellent run, if you can afford it.
For runs, some people also layer chicken wire with a stronger, heavier wire fencing, like a 2x4 woven wire. Either that works or people just haven't posted about it not working. The losses to dogs and raccoons getting through wire that I've read, have all been stories about plain chicken wire.
