I have a Russian Tortoise that a few weeks ago laid a yolk, no shell just a yolk, I looked every where on line for answers with no luck. I went to the pet store and they didn't seem to know what that was about either but said not to worry if she was doing well which she was.

This morning she woke me up at 6 a.m. and I knew she was ready to nest again. After she was finished I was excited to find two eggs. Later when I returned her to her inclosure I noticed another yolk which had to have happened prior to me taking her out to nest this morning. I was hoping someone could tell me why this happens or what it means... also I will be using a Still Air Incubator but the directions does not tell me if I should remove the red plugs (2) for air exchange now or closer to hatching. 

Hi
Sorry I can't help, I have never heard of that, but I will try to find out what I can.
Jane

Calcium deficiency??? I m just guessing.