With Corid you would have to treat your whole flock. Are you seeing any signs of diarreah in your other hens? Maybe people would recommend it, but i dont know to say yes or no.
How is her weight?
I dont know how are you administering a calcium tablet? She swallowed an entire calcium tab? I think powdering the tablet mixed with food would be safer.
Hopefully your hen pulls through. But based on the broken egg inside, antibiotic is a normal treatment. I think you could do corid, ivermecrin, and antibiotic without any negative interactions. Just the dosages are tiny of the ivermecrin and antibiotic.
If she is isolated, she could be treated woth corid, but you have to remove all the fresh water for 3 days or 5 days, so the whole flock would have to be treated unkess she has a isolated place.