So sorry for the loss of your friend. I know how there always seems to be one that outshines the rest when it comes to being sweet. She may not have been egg bound, she may not have laid an egg due to her being unwell for some reason you could not see. They hide illness very well. I'm not saying that to make you feel nervous, but if she'd been egg bound you probably would have noticed her acting strangely,and you can surely feel the egg in the abdomen. And sometimes they just die suddenly and we never know why. I know you're sad, but there was likely nothing you could have done. Just know you gave her a good home and lots of love & hang in there.