Could she be getting ready to molt, or just having a break in laying? Will she take a little scrambled egg, tuna, or cottage cheese? The cottage cheese or some plain greek yogurt can give probiotics. Can you feel in her vent with a clean finger for a stuck egg? I don’t know if giving calcium if she is not egg bound is a good idea. Calcium can be constipating, but if she is still making eggs, it is probably okay to keep giving. I really am not sure about that. Hopefully, she will eat and continue to be active.