That's a long time to have diahrea. Have you had a stool sample done for parasites? If not have one done. Buddy had gone through the same thing for 2 months. He lost 2lbs. Doc kept saying it was the food so I changed vets.
The new vet said nothing was in his stool however he wormed him anyhow.
There are times they do not show up and can be a male parasite. They do not lay eggs so there are no eggs to see in stool sample. It worked. After two months of looses stools it was normal in less than 48 hrs. Buddy is on
Natural Balance also since this happeded. He is thriving on it. I add some boiled white meat chicken to his two feedings a day. Take him off all dog food and give him only chicken (boil chicken breast) and rice. If this does not
harden his stools after two days contact your vet regarding parasites. If it does work add back food slowly. It it happens again might be the food.
Good luck. Carol & Buddy