She's very cute. The other commenter gave great advice. I'd also recommend top tier treats like watermelon or strawberries. I've never met a chicken who wouldn't swoon for watermelon.
Grab her and put her in your lap. Sit with her for at least 30 minutes. I use some paper towels under the chicken to protect from poop. Try and feed her while she's on your lap. The benefit to watermelon is she won't need water while she sits with you.
Going to sound stupid I'm sure but when you reach for her does she squat? If she does squat you're her rooster and if you don't, well, "mate" her, you are rejecting her and can absolutely lead to resentment. I like to pat their sides a bit. It lets them feel mated without actually mating them or being too weird lol and they start trusting you a LOT more. If she doesn't squat for you this approach is useless and she likely sees you as another hen.
If there is a rooster around, she will more likely than not, want nothing to do with being held because roosters are generally rough on hens. An all hen flock is considerably more loving in my experience. The second you add a hormonal monster in there it's really stressful to them. I lost the love of most of my hens because of this.
