Well if she's eating f/t that's not the issue, so you don't need to buy live. Also, a 35 gallon tank is pretty big for her, it's about 3 feet long and the rule of thumb is have a floor length that is 2/3rds as long as the snake. 40 gallon breeder tanks are often used for adult bps. As for feeding her, don't taunt her with the rodent, that can definitely scare a timid snake. put the f/t rodent in the tank late at night and leave it in all night, don't bug her, don't move it around, just drop it in and leave it. I would consider moving her to a smaller tank for awhile, if you don't want to do that you can try adding fake plants.