Here is what happen with mine I feed live (more convenient for me) however during the winter as my BP go off feed due to breeding I end up with too many rats, therefore I chose to euthanize and freeze them.

Once my BP resume feeding I offer F/T to half of my BP and they take it without problem, once I run out of F/T I feed them live again (I do that every year)

Note: all the BP eating mice eat F/T

After a year of trying, I have given up on getting my girl on f/t.
I am curious when you offer F/T and it fails do you offer live instead?