You may be asking if you really need poultry wire for your chicken runs?
Even though you are planning on having 'free range' chickens ... Unfortunately, you might still need to keep the chickens out of your garden. We talk about this more, in Chicken Coop Living, but the reality is this...
Chickens like a variety of foods.
And your garden offers one of the largest varieties in their world. So you may need to protect your garden from your flock.
I suggest a minimum mesh and wire height of 6 feet for fencing chickens in, or for keeping them out. WHY 'at least' 6 feet?

Poultry Wire / Mesh for Chicken Runs - 1" Mesh or Smaller is BEST!
Because chickens CAN fly!
Yep...
So, this height should detain most chickens from crossing over the tracks, as they say. To be honest, 6 feet is really nothing for some chickens, so you might need to think about taller fencing, OR a covered run area, OR clipping their wings.
In fact, I don’t know if you heard the story of how I lost 4 of my hens in one day? But, if you want to keep your flocks alive for more than a day, with certain predators, you’ll HAVE TO plan this features into your chicken runs. Of course you may not realize it until it's too late. Then BAM! They were gone. You don’t want that to happen to you.

Essential Chicken Run Tools for Attaching Your Chicken Wire