Birds don't learn about giving and taking. They're animals, they're not intelligent enough for most of what you're describing.
She wasn't intentionally looking innocent because she knew that you didn't want her doing that. She's a duck. Ducks are not capable of looking at animals of other species and deciding what they want, that's a very complex series of thoughts.
Either she had a hormone issue making her aggressive that resolved itself, or she got beaten up and ignored by the others every time she was aggressive until she figured out that acting not aggressive was what got her not beaten up and ignored. Basic "if I do A, then B. If I don't do A, then C" is much more simple than "the humans don't want me to do this, so I'll look innocent". How would a duck even know what a human thinks is an innocent look?
It's also possible that the current leader beat her up, and she doesn't attack it because she doesn't think she could beat it in a fight.