Egg mystery!!!!?!?!?

[Rhys1377]

Hi guys so I have a black australorp hen who recently went broody, so she laid her own egg which is unfertilised due to the fact we don't have a rooster whatsoever, we then we put 6 fertilised eggs under her without taking the unfertilised egg which she had laid. 3 days later we manage to get the unfertilised egg off her. We crack open the egg and the yolk was huge! We then crack a normal egg which hadn't been incubated and it was a much smaller difference compared to the other egg, so we are wondering how is this possible we don't even have a rooster???

 

[Free Feather]

The yolk size does not have much to do with fertility I think.

 

[dekel18042]

X 2. You have to look for the bull's eye to see if it is fertile.

 

[Rhys1377]

Okay thank you, I could see a bullseye but it isn't very big

 

[Free Feather]

There will be an itty bull's eye always. When it is large and pronounced it is fertile.

 

[Yorkshire Coop]

Here are some pics of fertile eggs https://www.backyardchickens.com/t/16008/how-to-tell-a-fertile-vs-infertile-egg-pictures

Yolk size would not make any difference to fertility as the embryo grows from the fertile bullseye and not the yolk its just attached to the yolk and when the chick is ready to hatch it absorbs the rest of the yolk into its body. This is how chicks can survive after hatching for up to three days. They have this happen so that the mother hen can still stay on the nest with the eggs that havnt hatched but her hatched chicks can survive untill she is ready to take them for food and water when the hatch has finished.