Pour 10 cups water into a 5-quart slow cooker crock; add sausage, carrot, celery, onion, chicken bouillon, bay leaves, garlic powder, and oregano.
Pour black-eyed peas into a saucepan; add enough water to cover by a few inches. Bring water to a boil, remove saucepan from heat, drain the peas, and add them to the slow cooker.
Cook on Low for 8 hours. Remove and discard bay leaves before serving.