It's very true and using 1/2" gauge wire is the key to protecting your birds. Your predators will be similar to ours, and it's worth the effort to protect the birds- and yourself!
Basicly YES! you could got a tab cheaper. Welded 2x4 wire lined with chicken wire but there is no guarentee that a raccoon isn't going to pull that chicken wire through the welded wire and then your chickens.
plasticoated 1 in. hex chicken wire. I'v lost doves to hawks, but only cause the fly around and go too close to the wire and the hawks reach in and grab them. I'v never lost a pheasant or chicken or had anything except a hawk get a bird.
Use 2"x4" welded wire for the "fence" part, and just put the hardware cloth around the bottom 2ft where the chickens would be standing.
No sense to put it up high, because a raccoon sticking his arm through it wouldn't be at chicken level anyway.
I used tin, it's cheaper and does the same thing.
If you are covering a vent or window inside a solid wall then yes, hardware cloth is the only way to go!
Think "Coop Knox" when you build, or else you'll just have to build it "right" the second time after all your birds have become KFC for some critter. Plenty of people on BYC can tell you that from experience!!!
plasticoated 1 in. hex chicken wire.
IS about the CRAPPIEST advice EVER! Chicken wire keeps chickens in --- and NOTHING else. It is NOT any use for keeping predators out!
It IS cheap if you just need to divide a chicken pen INSIDE an already-secure area, or use it to keep babies inside the daytime run if they are locked somewhere safer at night.
if rats are a concern, or if you want to be very careful that weasels don't get in, then yes, hardwarecloth EVERYWHERE ON ALL SURFACES (including top) is by far your best bet.
Frankly though it is real hard to keep out determined rats or weasels, and it only takes one little opening, so an awful lot of totally-hardwarecloth-everywhere runs are not honestly nearly as 100% safe as their owners THINK.
If you are willing to take a little bit of a chance with rats and weasels -- which I think is totally reasonable if neither is a huge problem in your area and the chickens are always shut up in a secure coop at night -- then another perfectly good option is to use a larger mesh wire for the run, like HEAVY GAUGE 1x1 or 2x4 wire mesh, or heavy gauge chainlink, and add hardwarecloth to the bottom 3' or so of it. It is really important to use a stout gauge of wire, though - the lighter weight 'garden fencing' type wire mesh, and cheapie chainlink, are not going to hold up so well to a raccoon or dog or coyote.