Fertile Egg?

[JewelBirds]

So it all begins with A. I don't have a rooster, but B. I might have a fertilized egg. I am hoping I am wrong, which is why I came here for a second opinion. I found a brown egg outside of the run in an old dog house that hasn't been used in a few years. The only chicken that regularly manages to escape out of the run is Azalea, my ISA brown, so I assumed that she laid the egg there. Plus yesterday I was watching her when she had gotten out, and she went to the dog house, I believe to lay another egg (which is actually how I found the egg in the first place). But she didn't like me there so left. I opened up the egg today, and I noticed something odd. A bullseye, white mark with white ring around it. But, we don't have a rooster. All 14 older hens (17-19 weeks) are laying eggs now, and the 6 younger ones definitely don't look or act like roosters (they're 14 weeks). What do you think? Is it fertile? And if it is, how is that possible?

 

[Lady of McCamley]

it's too hard to see the photo up close to tell. I think it is just normal variation of the blastoderm. A true fertilized egg has more yolk space between the rings. (I'll link photos below).

I can say with 100% certainty that without a rooster, your eggs won't become fertile. While sometimes dominant hens will take alpha type rooster roles such as protecting the flock, crowing, and even mounting, they cannot actually mate or fertilize another hen. It anatomically and genetically is impossible.

If the ISA brown escaped recently, it is possible she met up with a rooster on her illicit foray. Hens remain fertilized for up to 30 days (typically 14 days).

It is highly unlikely 14 week old birds, even if roosters, are able to mate and fertilize. They need to be sexually mature to do so. But, watch your flock in case you've got a precocious boy there.

My thoughts.
LofMc

 

[JewelBirds]

Thank you That helped. Yes, I guess I'll have to keep a closer eye on them (and her). Maybe I could put an egg of hers into the incubator just to see what happens.

 

[Lady of McCamley]

...and there would be your answer. If it develops, it's fertile.
LofMc