During the initial climb after takeoff, just after the aircraft passed 400 feet above ground level (agl), the pilot shut off the fuel boost pumps in preparation for the en route climb. Soon thereafter, one of the engines lost power without warning, and because he was carrying a heavy load, he immediately feathered the propeller and started looking for a place to put the aircraft down. Because there was rising terrain and scattered houses south of the airport, he had to maneuver to get to an open area. During the forced landing on the uneven terrain, one of the landing gear legs collapsed, and the aircraft impacted the terrain and slid into a power pole. A post-accident teardown inspection of the engine and the aircraft systems did not reveal any anomalies that would have resulted in the failure of the engine that lost power. PROBABLE CAUSE: “The loss of power in one engine, for undetermined reasons, soon after establishing the takeoff departure climb. Factors include rough/uneven terrain.”