mesh wiring?

Hardware cloth!


You should be able to find it at the feed store, possibly hardware store, etc...anywhere that sells fencing supplies!

 

Hardware cloth is great, but pricey. If you have 2x4 welded wire already, chicken wire inside might be ok . It will keep the birds from sticking their heads outside of the pen. I did chicken wire, but my pen is 185 ft around , 50' across anywhere, so coons cannot stampede my flock to other side for a partner to grab. Yes, they do that! And it has been seen done in broad daylight by a man who lost 3 before he could get out to the coop. Two coons tag-teamed the hens which were in a narrow 8' wide run.

 

It should be 1/2" to keep coon hands out.