I just can't help myself.
Snakes do not get or become lazy. They are only what their conditions allow.
Kingsnakes, heck all snakes, eat like pigs, when conditions are right. If they don't then thats a direct responce to conditions. Not a responce to being lazy. I imagine the possibility of there being a real truely lazy snake exsists, althought I have never seen one, the chance of having several or many is indeed rare.
I know, this is not what you asked, and I am sorry for that, but I thought this would be understood by now.
If your snakes are healthy(and I am sure they are) if you would allow a wider range of temps to choose from, they would without question, eat anything close to what resembles food.
If they are sick, then that may be reason for lazy snakes.
I hope I am totally off, so could you explain what a lazy snake is, and what are its choices? Thanks FR