What temperature does a bird egg die at?

Depends on if your refering to wild or domestic birds. In the wild, depending on the temperature. Birds do not leave their nests for very long and generally while one parent is out looking for food the other parent will be near by the nest. Eggs need to stay warm and humid and that comes from the parents. People who are bird breeders know that keeping eggs warm at all times is important. An embryo in an egg can die at room temperature in less then an hour. In the wild the embryo can die much quicker in high and low temps.