Ouen Kristensen born Sept 8, 1836 Skraastad, VA

Ouen Christensen and Aasne Syvertsdatter had 3 sons, Kristen Ouensen born 21 Sept 1865, Syvert born Dec 27, 1870 and Adoph birthday(?). All 3 emigrated to America. Could you help me find the dates they left and their destination. I have been trying to find them. I believe they are came from Strai, Oddernes. Thanks Suzanne