Hiya
I think it depends on where you are. Are there likely to be: raccoons, foxes, coyotes, rats, mink and their ilk, badgers, and other critters that feast on chooks?
If so, you have to put up wire strong enough to withstand them unless you've got ferocious dogs patrolling your run all night.
These guys can bite right through chicken netting, so you have to have wire strong enough to protect your chickieboos
Also, could they be attacked by owls or hawks, eagles? Then the wire has to cover their run.
Digging critters? Coons, fox, coyotes, badgers, neighbor dogs, will all dig under your fence to get that succulent chickie meat
We have all manner of evil things out there ready to attack, so on the advice of friends here at BYC our run is made of kennel wire dug into the ground 8 inches deep all the way around, and roofed with more kennel wire woven to the sides with fencing wire. It's completely intact.
The first week it was up something tried digging all around to get in - and failed! When it snows we see coon tracks all around it, but it keeps our babies safe.
When you want to raise chickies you need to run a layer of small-holed chicken wire around the bottom two feet of the area the babies are, just to keep them in.
It's work at the beginning, and not cheap, but then you never have to worry about it again, and you know your little fluff butts are safe.