She stated: "When I first read the book, I thought, 'This would be a great film,' and boy was I wrong. It's a much better TV series. Fast forward, I knew that Frank had initially developed it for NBC, which to me seemed like an odd pairing for this. Then I heard it wasn't going forward at NBC so I talked to Frank." On January 20, 2010, AMC officially announced that it had ordered a pilot with Darabont and Hurd acting as executive producers; the former wrote the script and directed the episode. The entire series was pre-ordered based on the strength of the source material, the television scripts, and Darabont's involvement. Frank Darabont wrote a 60-page pilot script for "Days Gone Bye". His initial script for the episode was split in half and embellished. Darabont explained that he did this to "slow the narrative down and dig into the characters more deeply, so it's not just plot-driven, event-driven stuff. You really want to drag these characters into the equation." Darabont felt that instituting visual maneuvers would increase the surreal atmosphere of a scene. Upon reading the script, Robert Kirkman thought that producers were consistent with his comic, adding that they could possibly improve his initial work. "Reading that pilot was just a revelation. It's extremely faithful. There are things that are so much like the comic, I can't really remember the nuance of what's different and what's not from the comic. He's definitely being more faithful than I expected, and everything that he's changing is brilliant. I couldn't be happier. I think the fans of the book are going to just love it." The episode shares its name with volume one of the comic book series. The principal photography produced a high demand for extras as zombies. In an interview with MTV News, special effects artist Greg Nicotero stated that while anyone was welcome to audition, the producers of the show were looking specifically for people who possessed exceptional height and thin features. Casting for extras took approximately three days. Once accepted, the extras would be sent to "zombie school" for training and preparing for filming. Nicotero stated that "it was interesting because I initially thought my experience with zombie movies is you just let them do whatever they want to do. George [Romero] always said, 'You show 50 people one movement, then you have 50 people doing all the same thing.' So we sort of just lined them up and said, 'Let's see what your zombie walk would look like,' and then they would do it and we would say, 'Try this or try that.'