Rooster and fertile eggs

[homestead 101]

How long after you add a rooster to a flock of hen will the eggs become fertilized.

 

[Pork Pie]

The best way to tell if you rooster has been doing his "job" is to break open an egg - maybe after a week or so of observing his efforts to mate. Here's a link that should help you determine if the eggs are fertile or not.

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

http://horseshoe.two61.com/files/2013/04/fertile-eggs21.jpg