For example, this is 72" x 50', 4" x 2" Mesh, Galvanized Welded Wire, 14 Gauge.
The welds in welded wire breaks easily. I've ripped any number of them string trimming the weeds/grass on a fence line.
The original request was regarding fencing but the thread has turned to a chicken coop building. There are a bazillion different ways to build a coop in this section of the site.
As far as the fence goes, skirting out keeps digging predators from doing so. Animals that tunnel like mice will eventually get in just because they naturally tunnel long distances. Your concern is the digging predators such as canines. They will start right at the vertical wall. You don't need expensive 1/2" hardware cloth to keep them from digging under, larger opening field fence will do the job because not only is it larger diameter wire, thus harder to break through, the holes in woven field fence are still smaller than the predator can fit through even if they do dig at the wire. You do need the 1/2" hardware cloth a couple of feet up the sides to keep coons from reaching through as was already mentioned. If you need to keep small weasels out, you are almost stuck with encasing the entire thing in 1/2" HW, those things can get through very small holes. And don't use Arrow™ staple gun type staples to install the hardware cloth, they pull out fairly easily. Use fence/poultry staples or a screw a board over the HC to the framing. The Arrow™ staples can be used to hold the wire in position.
Is your builder planning to do the fencing entirely with metal posts? T-posts or the round kind that are used for chain link? Either way the corners will need bracing to hold the fencing tight, a saggy fence isn't desirable, nor is one that is pulling the posts in toward the center of the run area. And, technically speaking, the "run" is whatever area you have fenced off for the chickens, doesn't matter if it surrounds the coop, starts at one wall of said coop or is a totally separate area.
I'm with
@aart on that video, it was well produced but I wouldn't take the coop for free.
Way too many design issues to even list and apparently a lot of people have her build them a coop? TWENTY SEVEN chickens in that coop? NO WAY. Even using the BARE minimum of 2 sq ft per chicken they would need 54 sq ft of actual usable floor space. If you look at that coop, it effectively has very little floor space because of the way the ladder roosts are positioned. An average large fowl standing is over 12" high.
It would be faster and cheaper to build a full height coop than one with a raised platform floor. Build using standard dimensional lumber and "sheet goods" and you won't have much cutting to do. Build it on bare earth and you don't have to deal with a floor. It is also easier to rake out the bedding if it is ground level. Put a removable 1x6 board across the door opening on the inside. When it is time to rake out, remove the board and rake into the run. Need more shavings in the coop? Walk in, cut the bag open and shake the compressed shavings out as you walk around. No reaching into the far corners from 4' away (how long ARE your arms?

) to spread it out.
Your question about roosts - you need a liner foot per bird, you want them as high as is reasonably practical and all at the same height if possible. ALL the birds want to be on the highest roost but if some are lower due to space constraints, the birds lower in the pecking order will be forced down.
And, by the way, if you followed a trail of feathers and found a chicken body part, more likely the killer was a fox and not a coon. Coons usually eat the crop neck and head, leaving the rest of the bird.
All of the above is my personal opinion, others may differ.