Incredible how nature works

In looking at a photo (taken by the owner of the nest box) of the egg that was removed, I observed an embryo in the remains. So the egg was fertile and was developing. At some point, the embryo died. Even a small crack in the egg would be enough to allow bacteria to enter and that could have caused death. Mother owl removed the dead egg from the nest box and actually ate some of the remains as you can see from watching the video. I hope that at least one of the other eggs is still alive and will hatch.

Hello! What happened? Why did the owl remove the egg?