I have a few snakes that were born August and September 2012. They are around 250 to just over 350 grams. They started out growing kind of slow when I got them, but seem to be taking off now. Since I got them I've been feeding about every 5 days, 10-15% of their body weight. They all look and act healthy, not thin. I don't have enough experience to say anything about snakes that are twice that size at that same age. It does seem like a lot to me, but I don't know.