I doubt that you can go back on the breeder unless you first find out what he died from.
Being just a puppy and having been left alone, he very well could have swallowed something.
It's a very sad story, and I'm sorry for your loss, but without an autopsy you probably can't do a thing.
Not to nit pick, but to inform. Kaw-liga was Hank Williams song, Not Jr's |