Originally Posted by gemy  Larry; I will tell you a story (a short one), I brought a 7month old puppy into my lifeabout 5 yrs ago now. She had a long long flight to come to me. At first her behaviour issues was attributed to that long long flight. A different breed to yours, and one that is much much larger. She was nervous, scared of many many things, loud sounds, the timer going off, new places, travelling in the car, and the list goes on. Her first un-solicited nip of human came 2 months after we had received her, on our way to the indoor swimming pool, no warning, no barks/growls, no body language change that we could see... And she was corrected immediately.
She went into intensive obedience training, instead of once per week, we did 3x per week. She was obedient, but also would shut down very quickly. The second nip of a stranger - this time I was on the lead, happened very like the first time, immediate correction. The third nip, was on that same vacation. On vacation, I called up a behaviour specialist to have her evaluated. Once their findings were known; I sought a second opinion. By now Zoey had a wonderfull recall, heel on lead, down/stay, sit stay, she retrieved toys like crazy and was quite food motivated.
The findings was of an unstable dog, likely genetic in so far as something in her brain was mis-wired. Conclusion no amount of training will make her reliable and stable.
We never gave up on her, but we were very cautious with her around strangers - she could never be trusted.
This type of problem is quite rare. And it is way too early to tell if that is what is going on with your dog.
It is quite difficult to offer advise over the internet, not seeing the dog, not seeing how the humans interact with this dog. I wish there was some magic bullet, command, or simple change we could offer you and your dog. But there simply isn't.
I am so glad you realize that 98% of the time it is the failure of we humans to train our dog, to find the way into their wonderfull being.
I offer this thought to you, if you think/feel you have done literally everything you can that you know; then it is truly time to seek the counsel of a specialist.
All I can tell you right now; if your dog is defecating on beds despite regular walks and potty time, and peeing all around, they need to be restricted in their free access to the house; as much as this might be a chore; difficult to institute etc. You have to go back to housebreaking as you would an eight wk old puppy.
If your dog nips people and most certainly you, then he does not get to have free run when guests are present.
And finally do see a specialist |