"You know, [Stephen is] a very busy guy, as of course is Joe Hill," Hurd told TV Overmind. "They've got a pretty full dance card, and in order to write an episode of The Walking Dead you need to be heavily involved in the writers' room.
"That's a commitment beyond just penning one episode. So it's difficult, for people who don't have a lot of free time."
Despite the famed horror author's absence, Hurd promised that every single episode of The Walking Dead will have "something that... will haunt people".
"Our seventh episode, which is the one that ends our mid-season before we pick up again in February, I think will knock people's socks off," she said. "People will remember this episode for a long time."