Its definitely something I wouldn't worry about, but also something that you want to keep an eye on. You just want to make sure you check on her, sometimes they hold it in until their next shed. Make sure you keep record of when she defecates, eventually you'll see the pattern and will know a little better if she's gone longer than normal. Typically they know what they're doing when it comes to that department. You can run into impaction issues but if you start to notice the tail swelling you can soak in warm water for a bit. Usually the warm water and then running through your hands a bit afterwards helps get them going.