Any update?
Could he have gotten into something? Any new treats? Dogs have very short digestive tracts, so when something irritates the system, it doesn't have a whole lot of time to "resolve" (like it
may in us). It's not all that uncommon for him to continue to try to "push" either - for the same reasons, not to be too graphic, that humans still have that urge when having issues.
Whether or not to go the vet sort of depends on his hydration level, your comfort level, his age (
puppies should usually go in ASAP!!), whether or not there was blood - and if the blood
continues (a bit of blood is usually normal in canine diarrhea). So, there are a lot of things that go into the equation - in terms of - "is my dog at risk here?" - you know what I mean?
I would also just throw in here, as a kind offer - that I'd highly recommed a different food. Bil Jac is a really, really poor food (sorry to say) - and long term - could cause problems, not to mention that it could be the cause of this short term issue.