I suggest giving calcium on the chance she has an egg stuck. It helps with contractions, but it also helps regulate the egg cycle. I use calcium citrate with vitamin D. One per day until the eggs are coming one a day max, and good shell quality.
Be sure she's drinking enough fluids.
I also...
Boy oh boy. Poor Rosie seems to have angered the chicken gods. Poor girl.
My biggest concern of all her travails are the two soft eggs. If an egg was broken inside her, yolk is a perfect medium for bacteria, and she may need an oral antibiotic if you suspect one of these eggs left some yolk...
ACV is a great additive to the drinking water and can help prevent many kinds of problems, but it's not a cure or treatment for disorders once they are established.
I would hold off on the calcium and give it only if you see the egg cycle or egg quality falter again. Then give it immediately...
That's good to hear that she's reverted back to solid shells and one egg per cycle. I suggest you get the calcium and hold onto it in case this starts up again. I keep a bottle of calcium tablets in my run so I can pop a pill into a hen immediately if I see she is starting to have egg quality...
What you're doing is focusing on a secondary issue when the issue behind it is going untreated. Those double shell-less eggs are the reason Rosie's crop isn't emptying efficiently.
Because her reproductive system is in need of regulating, the double egg laying can cause frequent blockages which...