[ponylady]

I have 20+ laying hens, mostly brown farm birds, plus a couple of Light Sussex and an Amber Star. I also have 2 Pekin cockerels, who live in big aluminium rabbit runs with their respective wives. They all live together in the same area, behind electric fence.
The Pekin girls have, naturally enough, produced fertile eggs, and yes, I know how to tell!
One of my big girls has been laying fertile eggs!
HOW??
She can get beak to beak with the boys, but they cant get close enough to .. err ... "do it" ...!!!

[doganjo]

Hmm .......  anyone heard of chicken immaculate conception 

They must be getting together somehow - or one of your hens has changed sex - that can happen - none of them started crowing? 

[Womble]

There's only one way to be sure - I think you're going to have to hatch some!!

[devonlady]

You've obviously hatched some otherwise you wouldn't know they were fertile. I once had a dog and bitch who, I'm convinced "did it" through the keyhole

[Clansman]

Ponylady just to clarify, are your fertile eggs actually developing during incubation or are you doing a visual check when you open them

[ponylady]

Visual check ... I cracked the egg open to eat it! Both fertile eggs had thin shells so didnt get put in the selling pile. I *think* its from my Amber Star, the eggs have stopped and she is sitting on foster children ...

[Clansman]

Have they been in with the cockerels a while back?

It's possible they can still be laying fertile eggs many weeks after mating.

Failing that are you 100% sure what you're looking at is a fertile egg?

[ponylady]

No, never had a cockerel in with the big birds.
Yes, doubly definitely certainly sure the eggs were fertile.

[Clansman]

Well i'm not a believer in the immaculate conception etc so there must be a reason for it.

Either as Doganjo says that you have or have had a "male" in amongst them you don't know about, the eggs aren't actually fertile, or someone's at it and pulling your leg! 

[roddycm]

It is possible to have fertile eggs without a rooster. This is called parthenogenisis, more common in turkeys though.

Here is an article that explains it better Super interesting stuff

http://www.thepoultrysite.com/articles/837/parthenogenesis-embryonic-development-in-unfertilized-eggs-may-impact-normal-fertilization-and-embryonic-mortality/

[Clansman]

Never seen that before, very interesting, Jurassic Park was right! 

maybe thats what you're seeing Ponylady? is it embryo development you can see?

[Cosmore]

Years ago I vaguely remember reading (probably in a biology book) that chicken eggs could be made fertile by inserting a needle into the yolk, stimulating the multiplication of cells into an embryo, can't remember exact details but it was along those lines.

[chrismahon]

We checked the blastoderm and those eggs certainly looked fertile. When it came to incubation none of them were, so we changed the cock and lo and behold all's fine. So how many hatched Ponylady?

[devonlady]

What did you actually see, Ponylady when you opened the eggs?

[ponylady]

What I actually saw was a fertile egg, exactly the same as the bantam hens fertile eggs, which have now hatched ...