I'm glad to here she perked up! It never hurts to add more calcium to her/their diet. Feed them eggshells or oyster shells if you want to add more, I can't really say if she became egg bound because of lack of calcium. A broken egg can also happen if she got banged up somehow, say from jumping off something into something else? I love it when things like this turn out to be happy endings. You are a good chicken mama!