If you truly have a picky eater changing prey type may not do anything.
I have a female hypo that barely passed the 1200 grams mark at 4 years old, I tried it all but she would eat one week and be off feed the next two or three months, nothing made it better.
At 1200 grams I decided to breed her anyway, she laid her eggs recently and since than is eating like there is no tomorrow.
I am crossing my fingers hoping breeding jumped start her metabolism in some ways, will see.
Keep your female in a 15 quarts as long as possible provide extra security and see if a different prey will work and if it does not than you know that you came across a truly picky eater and only time and patience will help.