You would think there would be something good for this purpose out there, but I have been severely disappointed. Here are my experieinces:
1. Roofing Tin. By far the best material. Must be 36" in height or you are waiting your time. No air pass thru. By far most expensive option.
2. Garden Weed Fabric. Cheap by comparison. Hard to keep it up. It is relatively flimsy and tears easily in the wind. No air pass thru but is a great site barrier. WAY too much trouble for us. We have tried various kinds and thicknesses.
3. Poultry House Siding. Couple of years ago was offered the plastic/material siding off of four chciken houses. Almost passed it up as was most interested in tin. This material is incredibly durable and will pass some air thru. The problem is that it is not a complete site barrier. For us it works well enough to keep the peacocks from head striking each other but we still get some psychotic attachment to walking along the barrier. Best material found to date but expensive unless you get it free like we did.
4. Black plastic sheets/rolls. Save your money. Tears down too easily in any wind.
While it does not pass any air thru, our favorite is the roofing tin. Both of our new pens have tin as the dividers. Above the tin and between adhjacent covered portions of the pens, we use the poultry cloth only during the brreding season. We roll it up out of the way during fall/winter. You must make the barrier at least 36" tall. Any less and they will just crane above it and head strike.