I would do a NILIF
type protocol and a bit of the two week shutdown
with any new dog brought in(not a baby pup, though) You need to set up the structure early on
Ah, NILIF. I didn't know there was a name for what I've been doing.
Short story: I bought my first two GSD's back about sixteen years ago or so. Not knowing anything about dealing with these dogs --as a kid we had toy poodles-- I got a trainer.
My first trainer was a lovely woman recommended by the local pet store. She took us through the early stuff and the usual cadre of pet dog commands.
When the dogs turned approximately six or seven months old it was painfully obvious she was way past her depth. The issues were particularly salient when she had to deal with them together. They pretty much walked all over her.
I had a couple of incidents of the dogs going off while walking them at the local promenade when coming across other dogs. As little puppies nobody cared. At seven months it must have looked like a nasty scary scene with teeth and barking everywhere. Few pet owners really understand dogs.
That's when I got someone to help. I didn't know myself. I thought I had a real problem in my hands. Someone recommended this guy who made it his business to tame aggressive dogs. He literally had a cage in his back yard. He'd put on a motorcycle helmet, heavy padded suit and fight the dog to submission. Brutal. Maybe some dogs need such an approach, I don't know. Thankfully I had the good sense to fire him before he took mine to that level. I felt he was just too rough in the four or five sessions we did just walking the dogs around.
I went out to find a trainer who knew GSD's. That's how I found this wonderful woman (she was early 20's at the time) who had grown-up training and competing Schuthund dogs.
I have to say that the approach and the results were incredible to me and to anyone who saw what the dogs became. We went to electric collars relatively soon (for communication, not punishment).
Anyhow, the lessons stayed with me. As per the NILIF approach, everything my dogs do is controlled. We have strict protocols about going through doors, entering and leaving the house, and car, etc. The kids learned these and apply them reliably. It works very well.
Of course, people who don't know dogs think you are being an absolute dominant jerk. I'd like to see them handle three GSD's.
the lines of your dogs play into what he is way more than who bred him.
I spoke with the breeder today to get a sense of the parent's temperaments. Nothing came up that would lead me to take pause. I was told his father, Oruger, doesn't like to let go of toys but isn't aggressive. That's probably a learned trait but I'll work towards a reliable release with Rocky anyway.
Thanks for the feedback. The only thing I didn't do is to remove the food. My older GSD's were treated to full control for the first six to nine months. After that the food bowl is always available. I completely forgot to take it back when Rocky was introduced. I'll do it now and control food for the next three months or so.
Not sure what to say about the no-walks idea. I took him on a relaxed two mile walk today and he did great. It was just him and me. Very basic obedience stuff. He doesn't pull on the leash so no real corrections there. I wasn't going to enforce a heel anyway. We just stopped at crossings until he sat down on his own and then crossed. I realize he has to learn about me as much as I have to learn about him, so I am being gentle yet firm and consistent with him.
Any other pointers would be appreciated. Thanks again.