Rosie O’Donnell, whose new daily talk show, The Rosie O’Donnell Show, will premiere on OWN in the fall, has been tapped to do specials for selected documentaries from the OWN Documentary Film Club, starting with Becoming Chaz, which will premiere in May. (It features Sonny and Cher’s offspring Chaz Bono). Meanwhile, according to the basic cable ratings released earlier this week, in its second full week on the air, OWN slipped to 310,000 viewers in primetime, down 20% from 387,000 the week before. (The network launched on Jan. 1, with an average of 1.1 viewers in primetime for its debut weekend.) As OWN is yet to bottom out, the network has fallen behind all of its female-oriented cable competition, including Lifetime (793,000), Oxygen (565,000) and WE (331,000).