I am Rick Grimes' missing hand
Frank Darabont & CAA Suing AMC Over ‘The Walking Dead’ Profits
I pumped Robert Kirkman for some scoop on the second half of the season and he offered up three interesting tidbits: 1) Carol will definitely return before the end of the season; 2) The Sanctuary, which was discussed in that radio message, will come into play; and 3) Via flashbacks, there will be glimpses into the lives of our favorite characters, likely including Michonne…
The Walking Dead News:

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He was the moral compass of the group and it’s always good to lose the moral compass. It will all become clear when we finally show you the back half of season 4. It wasn’t enough for these characters to lose the prison. They also had to feel some kind of loss over something important and Hershel was that thing that was important to each and every character, so it made the most sense to take him off the table and see how it affects the characters, which we’ll see when we come back in a bit. So there’s a lot of cool stuff ahead because of that.
The Walking Dead’s Robert Kirkman explained why Herschel needed to die and how it will impact the rest of season four:
Maybe she’s dead, but if she’s alive, that changes the story in some interesting ways moving forward as we go into some of the other stories from the comics that happened after the prison where Judith wasn’t present. It’s fun to think about how she could potentially change those stories if she is alive. She certainly could be dead. There’s a lot of blood in that car seat.
According to Robert Kirkman, from TV Guide about Baby Judith
OHHHH SNAP!!!

OHHHH SNAP!!!

The Walking Dead: A Decade of Dead

A Walking Dead Documentary

At the end, when Patrick dies, you realize that this is not an isolated incident. [Rick’s] pig is dead, we see the walker at the fence … it’s a ticking time bomb. Now, all of a sudden, [the virus is] right in the middle of the prison. We set up some great beats. Norman [Reedus, as Daryl] set up a great beat when he licks his fingers then shakes Patrick’s hand. You look at it and go, ‘Wait a minute, Daryl licked his fingers and shook Patrick’s hand and now Patrick is [dead].
Robert Kirkman on the Spanish Flu that is taking out the group
Pulling in a new threat in your fourth season, I think, is a good thing. Also, it’s important to know that this is really just some form of the Spanish Flu. It’s something that exists in our everyday world now; it’s a time where there is no modern medicine. Scott Gimple, the new showrunner, really wanted to explore that new possibility of the simple things, the really little things, coming to devastate these people. That’s what we’re going to explore.
Robert Kirkman on the new virus on The Walking Dead
Because he is amazing and very much fits the character. Abraham is a larger than life character that comes in and bowls over the characters. He’s just a take charge kind of guy and we need somebody that has that presence, that can stand up to characters like Daryl Dixon and Rick Grimes and really hold his own. This is a guy that can stand shoulder-to-shoulder with Tyreese and be imposing and that’s something that we needed and that’s something that Mr. Cudlitz delivers quite well.
We recently found out that Michael Cudlitz, formerly of Southland, will be playing Sgt. Abraham Ford. Walking Dead creator Robert Kirkman tells us why, in his mind, it’s a perfect match:

[Entertainment Weekly]