He'll be fine. A lot of times when you feed smaller meals the snake will store up the poop until a few meals worth and then rip loose. Poop smells and will pretty much alert other animals like prey animals that a snake is possibly around so they have evolved to hold their poop a long time. Now if after like 4 feedings and months later you don't see poop, then I would be looking to make sure there isn't any odd bulges in your snake like a backup or something but as it sits now, you are fine. just keep feeding like usual.
Matter of fact, I am going to bless you with some poo reading material!!! http://snakesarelong.blogspot.com/20...e-ballast.html