I bred my Dane Bailey about 16 months ago.
She had 11 beautiful puppies.
They all lived exclusively inside for the first 5 weeks. After that they started taking trips outside. I noticed that they would all go potty more outside. It was like syncronous clock work with them all.
I did not potty train them before going to their new homes, but I didn't have anyone report that they had trouble potty training their puppies. I think its much easier to potty train a larger breed puppy, considering they have a bigger bladder and can hold it longer.
When we got our new Dane puppy, she's 10 months old now, she learned to use the dog door within the first week. We hardly had any problems with her messing in the house. She was such a fast learner that she soon learned that if she just went out the dog door, she would get a treat. So she would just go out for a second and come right back in. We soon caught on to her antics LOL
I also think that potty training is subjective. It really depends on the individual puppies personality and how fast they will catch on to potty training. And it just so happens that your Aspen is a fast learner and has a innate behavior not to go inside his "den."
