stupid vampire
you dont kill your food supply... its messy leaves a lot of waste and cost more money than it saves
especially if you find satisfying bloodbags
killing them off by over indulging leaves you with a lot of corpses and the need to replenish your stock and worse the whole process might alert the public which could start a vampire hunt and that's just annoying if not dangerous
even humans a race that lives for consumption and exploitation knows to take care of its livestock