It seems like mine stick their ehads out when they're hunrgy. See, in the wild, they crawl into rodent dens while the rodent is away, and lie in wait for the rodent to come home, then they can just snap the rat up.
Usually, my full Bps stay coiled tightly in their hides, while my hungry ones keep their head out watchfully. But if they do this every day, it does not mean they just get fed! I have to fight the urge to overfeed sometimes, as I am sure we all do. But it just seems to me that mine stick their heads out more near feeding day than any other time.