A hawk got into my chicken yard, I have fishing line strung all over the top and cds hanging, it found a way thru the line and when I got out there it was running on the ground chasing my silkies. I chased it with a large pole net and it ran behind my coop and flew up to the top of the fence and escaped. They are smart and will find a way in you can't string every inch of space over your yard. We have now put heavy netting over a portion of the yard and fenced it off. If we see hawks the chickens stay locked in that section.