Most dogs are forever picking something up and eating it, whether it be rotten meat, old logs or branches, and no matter what kind of things he picks up, it has bacteria, maybe mice turds, ants, or larvae which can be found on old sticks or bark. I would venture to say that your dog has worms and the worms lay eggs in his stomach, so I would seek getting him de-wormed not only once but until you check and see that his stools are clear even if it means picking it apart with a stick to check it out.
Your dog relies on you, so it's your job as his protector to look after the things he cannot control. Trust me, you will never regret it, as a dog is your best friend when no one else is.
Your dog relies on you, so it's your job as his protector to look after the things he cannot control. Trust me, you will never regret it, as a dog is your best friend when no one else is.