Laura Dern has come aboard the Revolution-DreamWorks period piece “The Prizewinner of Defiance, Ohio.”Pic, based on the memoirs of Terry Ryan, concerns a couple who struggle to raise 10 children on the little money the mother brings in by winning jingle-writing contests. Julianne Moore, Woody Harrelson and Trevor Morgan have previously been announced. Also joining the cast is newcomer Ellary Porterfield. Jane Anderson wrote the script and is at the helm of the film, now lensing in Toronto. Dern, who recently wrapped Don Roos’ “Happy Endings,” next will be seen in Warner Independent’s “We Don’t Live Here Anymore,” bowing Aug. 13.