So when she began to act off today, I brought her inside and soaked her vent in warm water with Epsom salts then set her up in a box with food and water. I soaked her twice total and when I just checked on her, she had passed an egg that was basically just membrane with some clumps of powdery shell on it. She seems a little bit better, more bright eyed, but still is quiet (not normal at all for her!) and maybe a bit shocky? I'm obviously keeping her inside tonight and will reevaluate in the morning but I'm not sure whether her passing the "jelly egg" is a sign that she's on her way to recovery or if she is still in danger of being bound! This is my first time with both a broody hen and an egg bound girl... Not surprising that it would be this girl since she's a troublemaker but I'm pretty fond of her and want to make sure she'll be OK.
One other piece of info: she had never laid a truly dark egg like is typical of her breed but rather lays regular brown eggs with lots of dark speckles... Distinctive but not what they are "supposed" to look like. She has regular access to oyster shell and is on layer feed plus kitchen scraps and whatever she grubs out of the yard. Everyone else seems healthy and is laying well.