Two suggestions - one, wait a full week, and don't handle her, before trying to feed. Let her have time to adjust to the new environment without stress. I recently fed one of mine the day after I got her home... but she was incredibly comfortable and laid back, and was very interested when she caught a whiff of mouse on my way to feed the others. The second suggestion is, from what you said there it sounds like you you tried to feed her outside the cage. Don't do that - feed her inside the cage. It's less stress to her, and there's really no reason not to.