What was the breeder feeding?

It sounds like it could possibly be down to so many dietry changes. You need to stick to one very bland diet for a week or so.

You could try chicken and rice for a few days, and see if you can get some probiotics from your vet. Pro-kolin is meant to be great for dogs with upset stomachs.

__________________

I am just a worthless liar.
I am just an imbecile.
I will only complicate you.
Trust in me and fall as well.
I will find a center in you.
I will chew it up and leave,
I will work to elevate you
just enough to bring you down