How do I know if it's hatch-able?

[KikiDeAnime]

I found a small brown egg in the corner of our coop and when using my phone's flashlight, it looked weird inside. I'm not completely sure how old it is but I do know it's a pullet's first egg due to the fact that all our hens already started laying weeks ago.
I'm currently trying to find one of our flashlights so that I can take a photo to post below.
I know that our cockerel has only been going after the pullets since they're the only ones who accept him and I've seen him mount them a few times within the past few days.

 

[sourland]

It is generally not a good idea to hatch pullet eggs as their limited size can result in a stunted chick.

 

[KikiDeAnime]

It is generally not a good idea to hatch pullet eggs as their limited size can result in a stunted chick.

I wasn't planning on it. I just want to know if it's fertilized.

 

[sourland]

It may very well be fertile. If you are truly curious, crack it and check for the bullseye formation of fertile eggs.