Boil chicken and beef in a large soup pot 15 to 20 minutes, until tender. Use enough water to cover. Remove meat and cut into bite-size pieces. Discard fat and skin.
Melt the butter in a large saucepan. Cook onions and beef cubes until beef is browned and onions are tender. Add the beef stock, curry and bay leaves. Cook over low heat for 30 minutes.
In a large pot over high heat, boil the stew meat in enough water to cover the meat completely for 30 minutes, skimming the froth as necessary. Place the potatoes, carrots and onions into the pot, adding water if necessary.