Re: Biting when walking lead o
First - take a deep breath. Your frustration will feed the problem.
I'm not an expert, but Savannah used to do this to me when we were walking on-leash (as opposed to off). I cycled through a few alternatives - one would work during one walk, another on a different day. She eventually outgrew the behavior.
You might try alternating walking off-lead and on-lead during a walk so Penny has some game time and some work time. If your schedule allows, you might also take shorter walks more often. If Penny is getting over-stimulated, the shorter walks should interrupt the problem before it escalates. Regardless, as you know, she needs the walking time every day.
I used a toy - usually a small ball that could fit in my pocket - sometimes like Threefsh recommended. The stick you are using is working once, but try to find a toy that she will fetch multiple times. Throw the ball when she sits and looks back at you. You're trying to time the toy as a distraction before she comes back at you. The timing will take some practice on your part. Zukes makes some small treats that worked sometimes as a distraction, too. Again, as Threefsh recommended, command a sit, then treat. Always treat and toy only for success - never as a reward for bad behavior.
Believe it or not, what worked most consistently (but not all the time) for me, was sitting or squatting down, talking to her softly and either letting her sit in my lap or sit pressed tightly to my side for a few minutes. When she was calm, we would continue the walk. Think about how you calmed your kids when they were really young and overly excited. I don't know how appropriate this technique would be for your daughter, but you might try it to see if it works for you. My neighbor, who has a golden retriever, said she used to have to stop walks and reconnect with her dog during adolescence, too.
One last thought, it sounds like all the negative corrections are being perceived as part of the game. If so, those corrections are going to reinforce the problem.