Geez, I have 2 males that were bred and trained by me. No matter what I have 1 that will mark in my house. Doesn't matter how much I scold him for it he just does it. If they are pets, neuter neuter neuter.
But I bring my in-season bitches into the house - boys outside seem to be much more relaxed if I do that. I never had a problem with my older stud dog marking in the house (he knows better) until I brought in another adult boy, who was also well-trained in his previous single-male house. At that point it was a contest who could sneak a mark when I wasn't watching.
Recently rehomed my sterile sweet boy on Co-own. He marked when girls were in season. New co-owner is a vet tech. Took my boy to her mom's on the way home to her house. He marked at grandma's house, neutered next day, now a month later has never marked since being neutered. Best part is he is spoiled like a baby at new home and I was so afraid of placing him because he marked :)
For what it is worth, I have a young male who had not marked in the house. Suddenly he started marking in the house, in the garage and every place else (he was about 14 months old). No matter what I did I could not get him to stop and I thought his days as a house dog were over. Then within a month, both his mother and sister came in season. Once they were out, his marking in the house and garage stopped entirely and I have had no problems since.
I think he knew before I did that they were coming in season so I will be watching him in the future for signs that the girls are coming in season again.
No, it's not just a "training" issue. Try bringing in an outside stud dog - bet you'll get marking when you're not looking too. It's easy to be smug about how well-trained your dogs are until you throw a wrench into the situation.
