My neighbor is raising some young chickens (about a month old). He has them in a thing like a chicken tractor, made of a frame of 2x12's with 2" chicken wire nailed to the top. He drags the thing around with the chickens in it, to a new spot in the yard every day or so. All was going hunky-dory until he started losing a chicken every day. We were standing nearby talking about it when a tom cat that's been seen around the neighborhood for a while strolled over, hopped up on the chicken tractor and laid down. He then reached his right paw thru the wire and just let it hang there. Pretty soon a chicken came over to check out the thing hanging down, and Mr. Cat snatched it by the head and dragged it thru the wire. It took a lot of strength to pull that chicken thru that small hole, and it tore the chicken up a bit, too. Then off Mr. Cat went, into the bushes nearby, to enjoy his lunch. The whole caper took less than 30 seconds, from the time the cat first appeared until he was munching on his victim! But that was his last victim. He's now in kitty heaven. There seems to be a magic age after which cats don't bother chickens. But they are really bad on young ones.