How are you interacting with her? (Disclaimer - my chickens aren't pets, but I have picked up a few hints here on BYC for those who want them to be.) Do you chase her to try to catch her, or let her come to you? Do you try to grab her from above? How much time do you spend sitting quietly in the run or their free range area to get her used to your presence? It may work to sit out there and toss out an occasional treat. When she's used to coming to get those treats at a distance, don't toss them as far. Keep bringing her in closer that way. You may also just have to accept that fact that not all chickens are "pet" material. Some really just don't like human contact.