One thing that doesn't make sense to me is the total absence of walkers on the farm. In season 1 the walkers were coming up Stone Mountain and for those of you famailiar with the ATL area it's a fairly steep climb to by accident fall into the camp. Whereas Herschel's farm has livestock and there doesn't seem to be walkers for miles.
Why are the zombies ignoring Herschel's farm? Wouldn't a generator produce a lot of background sound to attract them? What about the lights from the farm house?