Following up on what Nanci said, the breeder I got my snake from said he was quite the runt when he was born. The breeder put a lot of extra time and care into taking care of him, sold all his siblings but kept him as his own. When I got him he was still pretty small for his age.
Now, he's about.. oh, 7 years old now? and is pretty big. Around 5 feet, maybe a little bigger now. I haven't weighed him for a while but he's a good healthy weight. He's had a few eating strikes and has gotten sick twice in the entire time I've had him, but overall he's a great snake, not many issues, and is certainly a ravenous eater. I've NEVER power fed him or anything--I guess it just took a little longer for him to get around to growing.
Just sharing my limited experience with smaller snakes :]