I did watch the "talking dead" show after the second showing of the mid season opener. They (the director) did let slip that there will be more zombies in future episodes ("we heard you") and that they will be leaving the farm. He did not say why they would be leaving the farm just that they would be. His statement about more zombies is that future episodes would be "zombielicious". Of course previous talking dead shows did state that in the comic, shane dies early on and this show indicated they did not feel obligated to follow the comic book all that closely. They also will not explore "what made the zombies in the first place. They just "are" and the show is bout dealing with survival in the zombie world. The preview showed the rest of the two dead guy's group pounding on the saloon door and asking about their buddy. SHOCK! Hershal had a gun in his hand next to the door and looked ready to use it on the intruders should they force the door.
Since lori crashed the car after running down a zombie while reading a map driving down the road (DUHH dummy!), I'm wondering if there is not a miscarriage in the works to remove the pregnancy complication. Unless of course she is preggers in real life then they will write around it or kill her off.