I was waiting fr the zombie swarm to get to the prison and surround the place. We saw the swarm a couple times where they saw the helicopter and started to head in that direction and eventually they came upon Hershel's farm. Then this last couple episodes when Darrel, Michonne and the two new black dudes ran into the swarm and had to bail out and make a run for it. One point early on there was talk about the zombies "herding" or forming herds of zombies. On one "Talking Dead" last year the writer and director sasi the upcoming episodes would be "Zombielicious" with lots of zombie slaying.