I used deer netting, not the poultry/bird netting you're describing you saw on McMurrays.
I got it for less than $15 a roll - I think it was about $12 if I remember correctly. It came in rolls 7 feet by 100ft. I bought 3 rolls for this project and used a little bit from an old roll I had already around the house.
The netting is pretty strong - I can JUST barely rip it with my hands if I really put my strength into it - stronger than I thought it would be.
It's strong enough to keep the chickens in. It would not be strong enough to keep a really determined predator OUT. My girls go up into their more or less predator-proof coop at night, and the dogs are on patrol during the day, so keeping the chickens in their part of the yard was the goal of my covering, not predator-proofing. Although, I'm sure the netting would deter a hawk, and slow down other critters.
You may have to experiment with various thickness and lengths of PVC pipe to see what works best for the span you want to cover. I think I really just about maxed out the width (20-25 ft) of the span for 3 pieces of PVC joined together. I think if your yard was much wider, you may have to put in a center support to help stabilize the PVC and control the curve.
Hope that helps!