I am only a hobby breeder but I try my best to feed f/t. keep in mind though the larger breeders may have a couple houndred snakes or more to feed and trying to do f/t would be a multi day event for them. I start my hatchlings off like this:
3 days post shed: live rat fuzzy
if they eat we do the same every 3 days for the first month as long as they eat.
if they don't eat the rat fuzzy I try every 3 days for 2 wthe eeks.
If after 2 weeks they havent eaten a rat fuzzy then I try live mouse hoppers.
generally the mouse hopper kicks the slow feeders off to a good start.
after a month of eating every three days I start offering pre-killed food and after two or three consecutive feedings I do f/t and usually by then even the stubborn have started taking rat pups of the appropriate size. My collection varies from 30 to 35 snakes and on a good feed day it still can take me 2+ hours to feed. so I completely understand why large scale breeders only feed live. as for the 150 200 gram 8 to 10 month ball..... ive only seen that age & size on really stubborn feeders so i'd steer clear of those. I have babies that hatched on 4/10 and are hitting 160 grams already. on the other hand I have one that has only eaten once since hatching and it still weighed in at 56 grams empty.