Thank you for your question. We reached out to our Vet Services Team and they sent this message along for you:
Thank you for contacting Doctors Foster and Smith with your question regarding the cause of soft egg shells.
There are many causes for soft egg shells. Calcium is only one of the minerals that are important for proper shell development. Other minerals that are also important are phosphorus and selenium. Vitamins B12, E, and D are also important for normal shell development. It is very important that your conure is fed a proper, balanced diet for optimal health. Some birds may require supplements as well, but this is best determined by your regular veterinarian.
Soft shells may result from medical conditions such as parasites, infectious diseases, and metabolic diseases. A physical examination by a veterinarian and the appropriate diagnostic tests would determine if your conure has an underlying medical condition resulting in soft egg shells.
Environmental factors can also affect the shell, resulting in soft shells. Such factors include excessive heat, stress, molting while egg laying, toxins (mold, fungi, bacteria), and other factors. A bird that suffers from chronic egg laying will also usually have soft shells.
In short, there are many causes for soft shells. We would strongly recommend a physical examination with an avian veterinarian in order to determine the underlying cause and to have the problem addressed appropriately.
Thanks again for contacting us. We hope this information is useful and the cause of your conure’s soft shells is not only determined, but also corrected.
Drs. Foster & Smith