Egg Color Genetics for Dummies

[hollandhens24]

I have chickens because they are a functional animal, but have grown to love them just as little yard friends. That being said, I also enjoy that chickens and their eggs come in all shapes, sizes, and colors. I have been trying to get "fun" colored eggs like blues and greens since I first got chickens and had rotten luck with my first EE getting eaten by a neighbor's dog. I purchased two Whiting True Blues from McMurray last spring, a hen and a rooster, with the hope of creating my own little rainbow flock. My WTB hen lays white eggs...my last hope was seeing what color eggs the pullets hatched this spring lay late this summer/fall (hatched March 4, 2025) to indicate that at least my WTB rooster carries the blue egg gene. To my surprise, I had this tiny little egg in the coop. I am not sure which of the pullets (2 WTB or 1 WTB x Silkie) laid it, but was surprised when it was cream, not blue like I had anticipated out of these crosses. I suspect due to the incredibly small size it may be the WTB x silkie pullet.

I have very limited knowledge of chicken genetics, but I was under the impression that the blue gene is dominant; therefore the offspring of my Whiting True Blue rooster and any of my flock: whiting true blue, australorp, welsummer, silkie, would all lay a blue or olive green egg. Can someone please explain to me the basics of egg color genetics that I am clearly missing? Either my silkie chicken had a fluke EXTRA tiny egg today, or one of my pullets has begun laying and has confirmed that neither of my Whiting True Blues carry the blue egg gene. What in the world has a girl got to do to get a blue egg around here?!

 

[Chicken_Obsesser]

@MysteryChicken

 

[MysteryChicken]

@MysteryChicken

Not exactly something I'm best in. I'm more into feather color genes then egg color since I've got more knowledge in that. I'm still learning Egg color genes, so I'll just wait for someone else on this.

 

[Slothinc]

The blue egg gene is dominant. However, it is confusing. Because if a hen only carries one copy of the blue egg gene, her eggs will be blue, but her offspring will only have a 50% chance of receiving the blue egg gene from her. If a rooster has one copy of the blue egg gene, then only 50% of his offspring will lay blue eggs.

So in the case of your silkiexWTB hen, she would have received a “not blue egg gene” from her silkie mom, and since she isn’t laying a blue egg, that means she received a “not blue egg gene” from her WTB father. However, it is possible that he does have one copy of the blue egg gene, which this hen does not receive. The only thing you know for certain is that both of the parents carry at least one recessive “not blue egg gene.”

With roosters, it is often easier to genetically test them for the blue egg gene if you want to make sure… otherwise you have to wait for them to mature, sire chicks, and those chicks to grow up and start laying before you can know if they carry the gene. Hens it is a little easier to know if they carry at least one blue egg gene, you will know when they start to lay.

To my knowledge, I thought WTB were supposed to have 2 copies of the blue egg gene. So that is a major bummer that so far your WTBs only one or none of the blue egg gene!!

 

[hollandhens24]

The blue egg gene is dominant. However, it is confusing. Because if a hen only carries one copy of the blue egg gene, her eggs will be blue, but her offspring will only have a 50% chance of receiving the blue egg gene from her. If a rooster has one copy of the blue egg gene, then only 50% of his offspring will lay blue eggs.

So in the case of your silkiexWTB hen, she would have received a “not blue egg gene” from her silkie mom, and since she isn’t laying a blue egg, that means she received a “not blue egg gene” from her WTB father. However, it is possible that he does have one copy of the blue egg gene, which this hen does not receive. The only thing you know for certain is that both of the parents carry at least one recessive “not blue egg gene.”

With roosters, it is often easier to genetically test them for the blue egg gene if you want to make sure… otherwise you have to wait for them to mature, sire chicks, and those chicks to grow up and start laying before you can know if they carry the gene. Hens it is a little easier to know if they carry at least one blue egg gene, you will know when they start to lay.

To my knowledge, I thought WTB were supposed to have 2 copies of the blue egg gene. So that is a major bummer that so far your WTBs only one or none of the blue egg gene!!

In emailing with McMurray Hatchery after my hen started laying, they confirmed that it was a fluke that could happen. I realize that technically WTB are basically an EE, but I sought them out because I thought there was a degree of predictability that made this breed desirable. I’ve only hatched 11 pullets from this rooster and my friend has 6 of them, so if neither of us get any green or blue eggs then I will have a definitive answer.

 

[Slothinc]

In emailing with McMurray Hatchery after my hen started laying, they confirmed that it was a fluke that could happen. I realize that technically WTB are basically an EE, but I sought them out because I thought there was a degree of predictability that made this breed desirable. I’ve only hatched 11 pullets from this rooster and my friend has 6 of them, so if neither of us get any green or blue eggs then I will have a definitive answer.

Yes, you should know for sure by the time all the pullets start laying. If none lays a blue egg then both parents do not have one blue egg gene. If one lays blue, and it did not hatch out of a blue egg, then your rooster does carry one blue egg gene.