Fertile eggs

[ducksssss]

How do I tell if my eggs are fertile. Can somone please help

 

[Miss Lydia]

How do I tell if my eggs are fertile. Can somone please help

https://www.backyardchickens.com/t/16008/how-to-tell-a-fertile-vs-infertile-egg-pictures

 

[ducksssss]

I meant for hatching I know how to tell once its cracked already but I woul like to know if my Indian runner pair has laid any in the past week... I have so many eggs I usually sell the fresher ones