Many breeders keep their animals on more of a maintenance feeding regiment rather than a growth oriented feeding schedule. This is just to keep their overhead down until the animal sells. I got a yearling carpet python that was 85g on arrival. The breeder was feeding him relatively small meals every 3-4 weeks. He wasn't unhealthy just small. After 6 months at my place he was up to 675g. They usually undergo a pretty big growth spurt once they're being fed a little more.