I feed my suriname girl every 7-10 days up to a year old. Then every 14 days until they are up to medium rats. Then every 3-4 weeks when on medium and large rats. Males get fed less.
They do grow pretty slow except they do have bursts when you upsize them a little. My girl is 1.7 years old and she just graduated to weaned rats. She's almost 3 feet long.
And i never go by the body weight thing for food. All my boas are fed just by the thickness of them vs the prey. Once they are adults, even that goes out the window and i just feed them a large rat or baby rabbit every few weeks. My big boas are all girls so i am a little more relaxed about their feedings and i also tend to feed a little more in the summer and a little less in the winter. It also depends on the food item. Rabbits are very dense so a little goes farther where as something like a quail isnt that packed with meat so i feed a little sooner if i give them one of those.
You can also read the boas. When they get hungry enough, they will start patrolling around. It's 4 days from feeding day for the little boas and my BCL and hypo BCI boys are both out at night cruising around lol. My suriname girl is in shed so she is quiet or else i would probably expect to see her out there cruising around at night too.
As for growth, most boas have a slow down at around the 3 year mark but they constantly grow throughout their lives. As for adult size, thats hard to say. I mean if you are considering 6 feet as an adult, then your boa probably wont reach 'adult' size until probably around 5-6+ years.
And here is a pic of Gina. She is a pure Rio Bravo Pokigron from parents from Gus Rentfro's 2006 litter.
