​Vampires need some tweaking

They seem to constantly use that leap attack even when they're nowhere near any enemies. Sometimes even when I have 30+ people imprisoned I get the message they don't have food. I go look at the prison - vampire is constantly leaping against the bars when trying to grab a prisoner to feed. They also feed to frequently so unless you're on a map with lots of spawning enemies you can't use them. Maybe that's intentional because they're so strong?