OP, I am truly so sorry you are going through this. I have been in those shoes, and words can’t really describe how it feels to euthanize a physically healthy, but severely behaviorally ill dog.

I had to euthanize my dog when she was barely 2 years old.

I started working with a behavioral vet, a CSAT, and a positive reinforcement trainer who specialized in guarding when my pup was 4 months old. She was consistently described as one of the most severe cases they had seen.

My vet behaviorist told me that level of behavior my dog displayed, at the ages she did, strongly indicated that this was a dog who would not markedly improve, even when surrounded by all the right interventions, strategies, medications, and so on. I’d always be one management slip away from a disaster.

Seeing some of the isolated behaviors my dog displayed, in an adolescent or adult dog, would be concerning, but likely manageable, albeit not curable. Seeing them in a 9 week old puppy is jarring and disturbing because it defies dog norms. And having a dog who displays a wide constellation of behaviors - or ticks many of the red flag behavioral boxes - is even less likely to have a good prognosis.

It is a sad thing that some dogs are wired wrong, and are not fit to be house pets or companion animals. You can’t train away genetics, or neurology, or early puppy experiences, or prenatal health, temperament across lineages, and so on.

There are many many many “gray area” dogs with behavior quirks that given the right person, patience, time, interventions, and modifications, can do great in a home. But there are also dogs who can’t safely be placed. And for some of those marginal dogs, there is no easy answer. Per myself, I ultimately couldn’t help P acclimate to this world. I loved her fiercely, and in the end, before a tragedy, I gave her a great last day, and then I gave her peace.

Be kind to you.