i'd suggest first that you ask the person you got them from what they were eating. Many snakes are idiosyncratic and/or habituated: they'll eat one logical food but not another, or live but not dead, or vice versa. So knowing what helped them get thru their first year would be useful ifnormation.
Second, if you can get a gram weight on them, it would help us here to judge whether they'vbe been feeding adequately or not before you got them.
Some of my nelsoni wanted to eat only frozen-thawed or fresh killed mouse fuzzies, a little smaller than they were capable of eating. Braining seemed to get a better feeding response, too. You may even need to try lizard scenting. But again, the best bet would first be to ask the seller what he/she was feeding them.
terry