I would agree that she is having some reproductive problems. Sometimes it may be not enough calcium to form hard shells, or infection in the oviduct, or she could have gotten exposed to infectious bronchitis at some time in her life. IB can cause shell gland problems, and hens can lay wrinkled shells, thin shells, or other problems. In cases like these where an egg has broken inside, some would use an antibiotic to treat any infection. Baytril, which is banned for chickens in the US, is sometimes used by vets. It is controversial to use Baytril, because of antibiotic resistance, but it treats many bacteria such as E.coli, mycoplasma, and others that may be common in reproductive problems. Amoxicillin is another one that is sometimes used, but it is not as effective on E.coli. If you can take her to a vet, that would be great. Here is a link for baytril (enrofloxacin) and dosage is 0.25 ml daily for a 5 pound hen for 5 days.
