I saw the preview on tv again today and I got thinking...
The old guy that owns the farm has to die. He's the only thing keeping them at the farm since he "won't leave". The farm is safe. This makes the farm unsafe, he'll die, and the group can now move on, pick up NEW people along the way and get the show moving forward for the next season.
Personally I'd like the see the wife go too, but with Dale gone, I guess they can keep her. The whole pregnant this is very much overplayed and jump-the-sharkish in too many shows.
It also a good time to lose some of the minor characters that aren't adding anything to the show. Killed, raped, and eaten, and if they're lucky, hopefully in that order.