HI,
I ve been doing a little research on boa speicies and possibly the general size for many boa's is gradually increasing, my guess is the breeders are keeping all the really large females for breeding stock. This could with time increase the average size of a species.
here's some adult BCC and BCI three of the animals are BCI..
http://www.mccarthyboas.com/BigSnake.html
this was posted on the MC CARTHY BOA PAGE.
most people who post on the web sites are keeping sub adults boa's .. The five year old boas are proably more close to the adult size,..
doug