I asked a similar question here recently and the answers were all pretty much along the lines of "They'll go when they need to go." Mine finally went after 3 1/2 weeks last night. Think about this... you have to match the size of the prey to the size of the snake because too small and they don't get enough to eat but too large and it becomes a race between digestion of the prey and rotting of the prey. If it digestion is that slow then it will certainly take a long time to work up a good BM. As long as your snake doesn't seem to be stressed then don't worry too much about it. All this from a total noob so keep reading for better answers.