Ok so she bit me again I was feeding one of the other girls and she came and started biting me !! This is ridiculous should I just feed the rest and not her? I think she is the Alpha of the pack ..
You're dealing with a hormonal teenager who's trying to take over the whole household. She's not only biting you, she's committing far worse a trespass- she's also at the very least kicking you and possibly starting the beginning of flogging you with her wings. She's treating you like you're a low-ranking chicken.
You're well past the trust-building part of your relationship- they know you and that you bring good things. It's a little like having a puppy- at first the puppy explores everything with its mouth, then it gets bigger and stronger and now it's biting, not exploring. While they look so much more grown up now compared with their adorable chick selves, they'll only be getting stronger and heavier- they're not done growing at 20 weeks, even as much as they've changed.
My suggestions to correct the situation: First and foremost, no more sitting on the ground to feed treats. You're putting your face and eyes at a level where one of these times she could easily jump up and cause damage. Second, no more hand-feeding. It's time to disconnect your hands and the food. Instead, bring their treats in the same container every time, then the container will mean treats instead of your hands. If they haven't already thought about pecking you when you reach in to handle them (because hand=treat and they don't care that they're biting you), it's likely to happen.
This doesn't mean cease and desist treat-giving, just no more hand feeding, and no more sitting on the ground to give them treats. Your chickens will enjoy their treats just as much from the ground. They'll still come running when they see you. First comes establishing yourself as the CONTROLLER of the treats, not the peckable treat dispenser.
Think of yourself as the granny chicken who gets her pick of everything before any other chicken dares approach the food. She pecks them and chases them off, has her fill, and only when she's good and ready do others consider approaching. Just because there's food to be had doesn't mean the youngsters get to run her over, bite her, scratch her to get it.
Use your index and middle finger as a beak. A peck to the head or back is speaking chicken and it means I'm the boss, not you. Nobody pecks the boss.
Pick a treat, put it on the ground, and then defend it like you're granny hen and that's the last food you're getting for the week. Anyone who comes in to nab it gets a "bite" on the back- you'll probably find they won't believe you at first. No anger or frustration behind it, just setting down new rules. They'll get the treat- when you decide to give it to them.
You may want to wear gloves/long sleeves/jeans and maybe even some eye protection the first time you do this with your naughty chicken. Have plenty of time when you do this for the first time. She will probably fight back- she already sees you as a subordinate chicken. That cannot continue. So, be prepared for her to challenge your leadership.
It probably won't be a whole lot of fun, but neither is having a chicken that treats you like this!