Having laid the shell-less eggs can be a calcium deficiency or a problem with the shell gland. A shell-less egg can be much harder to pass, and they can act egg bound, and sometimes the egg breaks in the process which can be a set up for a bacterial infection. When they are producing shell-less eggs, it can make them very weak and lacking energy. It sometimes can be helpful to give some human calcium for a few days to see if the shells become hard. But I would be tempted to also try some antibiotics at her young age, to try and prevent infection.