It varies from bird to bird. Give them the full course and it should clean up. Blood in the stool is not because of the cocci, but because of the damage done to the intestines as a result of the cocci. Small distinction, but important because your birds probably already have a much lower cocci load, but the lesions throughout their intestines can take a while to heal up and stop bleeding. That is why it is so important to treat cocci overload ASAP. Once the damage is too great the birds die from the cocci regardless of what you do for them because their intestines are too badly damaged to heal.
Good luck.