https://natureofpets.com/do-all-birds-lay-unfertilized-eggs/
Do All Birds Lay Unfertilized Eggs? A Comprehensive Guide!
Feb 28, 2025 - Not all birds lay unfertilized eggs. Some birds only lay eggs when they are fertilized.
do allbirdslayeggscomprehensive
https://www.livescience.com/64351-shark-embryos-swim.html
These Baby Sharks Swim from One Uterus to Another to Eat Their Unfertilized Siblings | Live Science
Dec 20, 2018 - The little sharks swim around inside their mom, switching between her multiple uteruses. When they get hungry they eat her unfertilized eggs.