Hi I had a similar problem with mine when I first got her.
She was drop feeding before I got her.. the shop/breeder left the f/t rat overnight and it was gone by morning style, but now she is settled in to her home she is striking like demon!!
what I do is leave the rat fluff to defrost next to her vent, so she gets the scent.
once it is completely defrosted I warm it (still in the packet) using hot water for a few minutes again left by her Viv.
I take rat out and dry it completely using paper towels, making sure its not hot but warm/+ warm. drying it makes sure it get no substrate stuck when it drops
She is then in her hide (head out) or sniffing round the vent and when I lower it in a jiggle it a little, within a second she has it in her coils.
but don't worry, mine went off her food for 2 weeks when I got her.
The shop had her in a plastic tub and now she is in this:
not surprising she is now feeding more naturally, and i'm sure having the rat warmed helps them target and gets them in the zone lol