Desert Tortoise Shell coming off

Question
I have a desert tortoise who is 17 yrs old.He was born in our captivity. He cruises around in the backyard eating hibiscus flowers, grass, and other veggies I give him throughout the week. He has always been very healthy. This past winter he started hibernating in a corner of my backyard with mud. He was outside in all of the California winter weather for a few weeks before I put him in a box in the closet. When he awoke, he was just his normal self. A couple of days ago, I saw part of his shell on the ground. It came from his horn under his neck. It came completly off. His rough,dry skin is exposed and it looks just like his leg. Inside the shell looks like dry mud. If I tap his shell next to the piece that came off, it sounds hollow. What is going on?? Can you help??

Answer
I cannot help a lot with this, but luckily, the state you are in has a great turtle and tortoise club that can help- contact http://www.tortoise.org and find a chapter near you to find someone who should be able to help a lot!

Or, you can try the forum http://www.tortoiseforum.org to find experienced keepers in a site where we can ask questions, see photos, etc. more easily!

Sorry I cannot help, but good luck!