If your 4 months old puppy has had 4 series of shots administrator from home and bought at tractor supply has diarrhea what is the chances of it being parvo

Personally, I wouldn't take ANY chances with parvo. And there's other stuff out there that can be bad, too. At minimum, take in a stool sample and provide any symptoms your pup is having.

Highly possible if the shots weren't handled properly (in transit or at the store)

I would give them a call, make an appointment . Vet is very good. Could probably tell you pretty quickly if your puppy has parvo.

Very slim. It's most likely giardia or coccidia