The cheat doesn't work anymore. As soon as they put out the patch they fixed it. I tried to get this one and now it's damn near impossible. The chickens spawn to slow the farmers walk to fast and when I shoot into the crowd of chickens I only hit 1 out of 4 even when the redial turns red. I can't get past at most 308. Not only that but the aim assist on the xbox is non extant, unless your dead on target (and I mean dead on target) the shots don't count as a hit even when the redial turns red (this happens with snipers too). I could see doing this with a mouse and keyboard (but even then it would be a stretch), it's just the xbox controller can't keep up with the precision aiming that's required for this challenge.
As of a few minutes ago (xbox360) one of the chickens that spawns on a post is never picked up by a rancher. I cheesed this one pretty easy just killing him, counting 9 seconds and killing the chicken that spawns on the ground, and then killing the chicken on the post again as soon as he spawns - if you count to 9 before you kill the ground chicken, you should be able to maintain the kill chain to get the score up.
I was pulling my hair out trying to do this legit. Ridiculously aggravating challenge. Dealing with the shame is easier than dealing with the seething rage that was building up from trying to do this one legit.
Now I'm gonna go get a bucket of chicken. That's right, mothercluckers. I win.