I don't have any experience with BRB's, so unless there is something specific they need, I can assume feeding them F/T would be similar to any other snake. Have you tried using a hair dryer to heat up the prey right before offering it? Try thawing the prey in the snake room and while you are heating it, use the hair dryer to blow the scent towards the enclosure to pre-scent it. That's about the best I can offer for now...