Welcome to YT! I would definitely neuter the boys sooner than later. Intact males usually do mark, and now that one or both have started marking, it may take a while for them to stop even after being neutered. You may want to consider belly bands in the meantime. Bottom line - neuter, neuter, neuter! It also makes for less health problems as they age.
__________________ "The little furry buggers are just deep, deep wells you throw all your emotions into." ~ Bruce Schimmel   |