As I just told the breeder, we opened her up. Looks like her heart exploded. There was dark arterial type blood that gushed from the heart and half of it was completely deflated. Also, the sac around the heart was filled with fluid. We found several yolks that were developing, but no egg ready, and the other organs seemed healthy, at least there were no lesions that we saw.I took pictures of the necropsy we did and will see if I can find some reference pics. I'm so upset about this. She was beautiful and healthy-looking. At least I did notice that something was off yesterday, so I wasn't completely surprised, but this is so upsetting. Again, something I could never foresee nor prevent, I guess. Darn.