I used to have a Rescue that weighed 4500 gr. She looked huge ! Had a very big head for a BP.

She laid a clutch while in my care (Surprise...) and the clutch weighed a whopping 1400 gr. 6 eggs, one went bad. Largest hatchling weighted 116 gr out of the egg, smallest one 89 gr.

I absolutely believe that size is genetic. And that there is a line (whether that is geographically related or not) that grows bigger BP's. Not talking about fat/obese ones either, just bigger all around with really big heads.

I have a male that is bigger, always grew faster and bigger then my other hatchlings (all same year, all same diet), too.

From way back I remember a Jared (forgot last name) having a HUGE Ball Python female named Big Bertha. The pic is still floating out there, somewhere...