Hi Cara - I just saw and read your whole thread. Bella is very much loved
It's so hard with these things because each of our feathered friends has their unique traits.
I have Ellie, who eats everything under the sun and lays picture perfect eggs. She prefers my roo's game bird maintenance food to layer food and she self supplements with oyster shell that I keep available 24/7 in a separate bowl.
I had Annie, who did the same and would always fill up on oyster shell the night before laying an egg (I think to replenish the calcium that was used to make the egg on its way out) - she laid an egg every other day. Always perfect eggs. Sadly, I lost her to a heart attack before her second birthday - cause unknown but it could have been in trying to pass an oversized egg (that day's egg never came), though she had never had trouble before, as far as I could tell. She had such a beautiful spirit - it was heartbreaking.
I had Betty, who unfortunately did succumb to internal laying. I had a hysterectomy done on her but she was too compromised to come back from it -many do just fine if they have this surgery sooner. The vet had been treating Betty with antibiotics and antiinflammatories and that did help for awhile but in her case, it then stopped helping. I was sad to find out that there were many festering eggs inside her when he opened her up. Betty had struggled with soft shelled eggs. She also
detested layer food. Chickens living a more wild existence don't get any layer food but do just fine - they figure out what to eat in nature. Betty enjoyed finding things in nature to eat. It really is hard to figure what causes this problem - we humans may have bred these poor beings to be predisposed to having the problem regardless of feed choices. Though diet is certainly important.
Try keeping the oyster shell separate from the food and see if she makes a point of eating any. My birds have always received healthy treats, including sunflower seeds and fruit and veggies. But during early morning and in the evening before their bedtime I have only the layer and the game bird maintenance available, to hopefully ensure that some of this stuff gets consumed. They have some free range time each day to choose what they want from nature. Try also perhaps adding something like Avia Charge 2000 to the drinking water. It contains various nutrients that may help bolster her. You can order it online. I use it daily but more diluted than the instructions call for, as they don't like to drink it otherwise.
I hope your sweet Bella will be okay. Keep us posted.
JJ