I meant to add, yesterday, to Velvetfog's list of wire types some that he's missed: cage wire, and various types of livestock panel.
But first, a digression on the subject of "hardware cloth." The stuff recently available is to what I first experienced as real hardware cloth as surgical gauze is to canvas: utterly unsuited for the same purposes. Real hardware cloth was both woven and welded, and had to be cut with heavy tin snips. It was serious stuff, intended to be used to make foundation vents rat-proof and keep gravel from clogging french drains.
1/2"X1" Cage wire is somewhat better- you can't inadvertantly break the weld by putting pressure on it, for one thing!- but is still welded without being woven, so that only the very small weld is holding the wires together: this is not, and will never be, sufficient to keep raccoons or people or large dogs out of your pens. My permanent pens have overlays of wire, mostly Livestock Panel/Pasture Fence/Yard Wire/Hardware cloth on the bottom 24" phasing to yard wire/chicken wire on the top foot.
(I'm leaving out the whole matter of cyclone fence, which is too heavy to move without equipment, expensive, hard to stretch, and not raccoon-proof, where "raccoon proof" is, I think, the ultimate goal, unless you're in a high density bear zone). (Not to mention various vinyl products, which I see as a way to make chewing through corners as slow and unpleasant as possible, and needing to be checked frequently to make sure such chewing is not in progress).
Pasture wire, by the way, is a woven grid that starts at 2 1/2"X6" at the bottom and gradually increases to 6"X6" at 62" tall; properly installed it has a run of stretched barbed wire or a hot wire at the top. It is meant for sheep, cattle, and horses but reinforces and strengthens chicken pens.
Livestock Panel is heavy, rigid, welded then galvanized wire too large in diameter to cut quickly without a cold chisel and sledge, grinder wheel, or bolt cutter: when I cut it myself I sacrifice a wheel on my plumber's tube cutter to score the wires and then bend and snap, a thankless job to be sure. It's grand stuff for keeping cattle out of tasty gardens and landscape plantings, it's what I used to build Bacchus's sheep tractor (and to trellis the Climbing Hydrangea) and, if I were rich, the Hamburg Extension University the wow very expensive yowza 4"X4" grid would be the framing and roof; I'm trying to torture the math to buy a piece of that to roof the Wyandotte pen, as I figure it's the closest to raccoon proof as anything short of expanded steel walkway.
And a note on VS's assessment of chicken wire: the old stuff, and possibly the stuff used by professional chicken-factory builders even now, was double-twist construction in heavier gauge wire, and was (if memory serves) 3/4" and 1 1/2" rather than 1" and 2." My BIL may have a line on some very old wire stored out of the weather and damp, which would be a dream come true.
I saw an ad on cl this morning for some kind of expanded steel- not walkway, I think it might be heavy-duty air intake housing from a high-capacity HVAC system- which would be a grand kind of stuff for unlayered use. Expensive, but looks to be certain of keeping out anything bigger than a mosquito. There's a whole lot of material on the planet which is too expensive to use for chicken housing when looked at full price, but which is the best ever when scrounged.