Well, initially I would have though Glynda or Phyllis, as they are both curious and good flyers. But then, I realized you said 'flimsy fence'.. If someone flew over it, you wouldn't be saying 'flimsy', you would be saying 'short'. So, given this, I am going to go with either Hattie or LAdy Featherington. I don't think Eowyen would breach the fence, nor Betty (though I may be surprised...but if she did, she would have flown over) Also, Sydney is a good flier as well (witness: her taking Ned & Lucky into the tree!) I don't think it is Gucci, as she is just starting to see, and needs time to get her confidence up.
Aurora I don't think would bother breaching into the littles, they are, at this point, beneath her/ not her worry as head hen That may change when they mingle, though.
Hmmm, I just read your list again, and Hattie was not on it. (?maybe she is subdued due to molting?) so, i guess by process of elimination, that leaves Lady featherington? She is a bold one...playing 'one foot out/one foot in' with you...so Lady it is!!
Hattie was excluded as she is molting and has interest in nothing.
and I was wrong! 
LF would have been my 3rd choice but I am still surprised it wasn't Glynda.
he gobbled it right down. He’s such a good rooster! He’s been watching over little Dakota too.! Sometimes even a roo like him needs a bachelors time out. This time it’s a steak dinner! I love my sweet rooster Jaffar! He really is a feathered miracle! 
