You know this has been going on for what 2 months now? Ascites or egg yolk peritonitis is often a result of the continuous laying of shell-less eggs. You always have seemed to notice when she is struggling to lay or feels awful, then comes the shell-less egg found. You have given the calcium so long, that it probably is not helping. Honestly I probably would have probably given up weeks ago, and put her down, poor thing. I realize that you are fond of her, but it doesn’t look like she is ever going to get better. I am really sorry, Vartain, but I thought that she was dying a couple of weeks ago. The other chickens seem to know that a sick chicken is sick, and they will attack. I have seen it time and again with former flock leaders and even roosters who were felt to be ill. It would be good, if you can manage it to do a necropsy when she does die, just to see what was going on.