Go to the vet, not just when he is sick. Annual checkups and lab work. Get a diagnosis and see what the vet advises.
Blood in the feces is not normal, eating grass is not good, something is wrong.
Best of luck.
PS: /disclaimer-and-disclosure/ excerpt below
Please be advised that we not veterinarians. For this reason, this website was never meant to be used as a substitute for sound professional advice.
Because the health of your dog can be directly affected by what you read here, you should always consult with a licensed veterinary professional before taking any specific action.
3 months, 1 week ago
