Disney's Pixarless CGI flick Chicken Little ruled the weekend box-office roost, debuting at No. 1 with a better-than-expected $40.1 million. Iraq-war drama Jarhead also opened strongly with $28.8 million, good enough for second place. Still, total receipts lagged 10 percent behind the same period in 2004, when The Incredibles premiered with $70.5 million.