Steve Oedekerk, whose screenwriting resumé ranges from cult items (Kung Pow: Enter the Fist) to studio projects, both animated (Jimmy Neutron: Boy Genius) and live-action (Bruce Almighty), wrote and directed this Nickelodeon cartoon feature about barnyard animals whooping it up while the farmer's away. It's way funnier than many of the R-rated comedies I've seen lately, though Oedekerk seems to have ignored the writer's edict to know your subject—most of his cows are male. The CGI is excellent, with characters whose depth and solidity suggest Nick Park's clay animations. The laughs subside near the end as the requisite moral kicks in, but this is still that rare kids' movie I'd recommend to parents and nonparents alike. With music by the North Mississippi Allstars. PG, 90 min.