Young carpets usually require the stimulation of tease feeding...not the bounce it around style that you probably use with BPs, though. Obviously, (if the hoppers are the appropriate size for them) these guys have been feeding fairly well, so you may not have to do too much messing with them. Babies respond best to sort of a "tap tease", in which you touch them with prey item - NOT ON THE FACE. lightly touch the body then quickly move the prey item up and tap the snake on the neck (hard to say how far down from the head without knowing how long they are). This should stimulate a strike. If not, do it again on the other side. Once they are feeding regularly, you shouldn't have to work that hard to get them to take food - but sometimes (new environment) you have to drop back to jump start them. Another thing that helps is giving them something to perch on, as young carpets tend to be fairly arboreal.