I just read that, while trying to find an answer. It's a very interesting topic.Very rare.
For example, here's an article from 1968:
https://academic.oup.com/jhered/article-abstract/59/1/67/821031?
It references one researcher who found 3 developing eggs among 1022 unfertilized eggs.
Of those three, one chick hatched but only lived 8 days, one died on day 23 without hatching, and one died at 7 days incubation.
(That is on the first page of the article, which is all I can see.)