Craig Mazin says he knows what you’re thinking: “The Chernobyl and The Last of Us guy wrote a broad comedy mystery about talking farm animals? OK.” Well, Mazin’s comedy roots run deep. Also, we contain multitudes. The Sheep Detective s, Mazin’s adaptation of Leonie Swann’s Three Bags Full , has been a passion project of his for the better part of two decades. And now that results are finally out in theaters — the feature includes an impressive cast on-camera (Hugh Jackman, Emma Thompson, Hong Chau) and voicing sheep (Julia Louis-Dreyfus, Brett Goldstein, Regina Hall) — he seems a little nostalgic. “I feel like this is the one where I finally figured it out,” he says.…