The Kentucky Derby 's famously chaotic start, with twenty horses bursting from the gate in a mad dash , often decides the "most exciting two minutes in sports" in mere seconds. This year's 152nd running, however, is exceptionally wide open. Even veteran race caller Larry Collmus, who typically zeroes in on the frontrunner for NBC 's television broadcast, admits to being stumped by this year's challenge. "I don’t know who the favorite is going to be," Collmus said. "I guess we’ll find out. It’s wide open this year." Todd Pletcher-trained Renegade opened as the favorite, but the top spot could easily shift to Brad Cox’s Commandment or Further Ado, or Bill Mott’s Chief Wallabee, before the 20-horse field leaves the gate. The Triple Crown's first leg is so wide open that at least a half-dozen horses possess a legitimate chance to win the 152nd running on Saturday.…