It depends from snake to snake, like somebody mentioned and they do need proper heating temperatures to properly digest their food although by nature, their body temperature slightly increases during digestion, and this is when mine tends to frequently thermoregulate (moving from cold side to warm side). You can always give them a warm soak for a few minutes which always helps pop things out a bit. But normally the day before poop time, they look like they're about to "pop" right at the tip before their tail. I'm sure everything's fine. It's when they don't poop for a while that you should be concerned. Good luck