Is it hot where you are? Are these her first two eggs? She many work it out on her own if these are her first attempts. Sometimes the gal's ability to absorb calcium decreases in the heat. She also may be stressed, have an immature shell gland (or glitch in her uterus), or simple have a nutritional deficiency (calcium, phosphorus, vitamin D)
Crushed egg shells always work for me to solve rubbery eggs and I've never found it to encourage egg-eating. I would suggest separating her in a dog kennel with lots of food, water and egg shells for the day