Blue Egg Gene: Genetic Testing for Chickens {Visual Tutorial}

Here’s a visual tour of the entire genetic testing process that was performed for my Whiting True Blue chickens and a couple other colored egg layers in my flock. Blue egg genetic testing is EASY, especially when using feather samples! I used Freshly Picked Chicks DNA Lab for the test and here are the results:

Genetically Testing Your Flock for the Blue Egg Gene

The blue egg gene is an incompletely dominant gene on chromosome number 1. The blue color in the egg shells of birds is called oocyan so the abbreviation for the Blue egg gene is a capital letter O to signify the oocyan blue egg gene is present. White egg shells in poultry are recessive so they are represented by the lowercase letter o to indicate the trait is recessive and the absence of oocyan.

2 Copies Better Than 1?

Because the blue egg gene is incompletely dominant, the presence of two copies can produce a richer, better blue egg shell than just one copy. When a bird carries two copies of the blue egg gene they are said to be homozygous which is written as (O/O). If a bird only carries one copy of the blue egg gene, this indicates it also carries one copy of the recessive white egg gene and the bird is said to be heterozygous, also called a split, which is written as (O/o).

Testing for the Blue Egg Gene

Genetic testing can be done to determine if a chicken carries one or two copies of the blue egg gene. This is performed using small laboratory equipment to extract the DNA from blood or feather samples and then use gel electrophoresis to make the genetic results visible to the human eye.

Step 1: Purchase the Test

The first step is to purchase the Blue Egg Gene genetic test. This is done online using a secure checkout platform.

Step 2: Print the Paperwork

You’ll need to submit paperwork with your blood or feather samples. The paperwork is available as a digital download when you make your purchase for at-home printing. You can print as many copies as you need.

Step 3: Choose Your Sample Type

Birds over 3 months old can submit feather samples, which I found to be the easiest. See the video on how easy it is to collect a feather sample. Blood samples can also be collected and submitted. You’ll need to be VERY careful to not cross-contaminate the blood samples. If you need to test chicks, it requires submitting a blood sample.

Step 4: Fill Out Your Paperwork

The DNA Sample Submission Form is one of the sheets you printed from the PDF download. Fill this out with your sample number (1,2,3,4, etc) and the Bird ID/Name. It is a good idea to have the birds name AND his/her leg band color or number included on this line. Fill out the breed or hybrid cross. Fill in gender if known. The blue gene and recessive white columns remain blank for laboratory use.

Note: Filling out the breed/hybrid information correctly is an important step that helps to identify each bird. OE for Olive Egger, EE for Easter Egger, PBE for Prairie Bluebell Egger, WTB for Whiting True Blue, CL for Cream Legbar, AMER for purebred Ameraucana and “Barnyard Mix” are all fine to enter. If you created the cross and know the parents, things like WTB x EE are great to note. You will want these details when you refer back to your genetic tests and when you show the results to prospective buyers! If you do not fill in the breed, you have no proof you had that breed tested.

Step 5: Collect Your Samples

This step requires some supplies. For feather samples you will need individually labeled ziplock bags (I used snack size) and a permanent marker to label each ziplock. You cannot put too much info on each bag! Sample number, the bird’s name, leg band color, your farm name – include it all. Blood samples require you to fill out each Blood Sample card. Your samples should each be numbered and correspond to the numbers on your paper submission form.

Step 6: Double Check Samples and Prepare for Mailing

It is a good idea for your paper blood sample cards to each be in an individual ziplock bag to protect them from moisture while enroute to the lab. Use any envelope to mail the samples to the address provided. I made the mistake of not purchasing tracking and my envelope ran into some delay, not arriving for 8 days. Tracking is worth purchasing for the peace of mind!

Step 7: Mail Your Test!

I popped into a post office to have my envelope weighed and mailed. (Remember to buy tracking!) If you aren’t shipping by Priority Mail, the post office needs 5-6 full working days to get First Class and Ground Advantage mail to its destination.

Step 8: Wait for Results

Once your envelope arrives, Shannon at Freshly Picked Chicks is VERY FAST in the lab! There is around 6 full hours of work to be done just to isolate the DNA from each sample, prepare a fresh gel electrophoresis plate and then run your samples, all of which are carefully handled and labeled at each step. It takes multiple hours for the tiny bits of DNA to physically move through the gel to create the bands visible to the naked eye which are interpreted to give your genetic testing results.

Tests are processed in the order received and your results are emailed to you 24 hours after your envelope of samples are received. Farms testing large flocks (over 32 birds) requires more time in the lab to isolate the DNA from each bird and run multiple gel electrophoresis plates. You’ll receive an email as soon as the results are ready and the information can be entered to send to you!

Testing Process Pics:

Shannon at Freshly Picked Chicks has generously shared images from my genetic testing process to give us a behind-the-scenes glimpse at the Freshly Picked Chicks lab:

Your Results are Confidential

What is emailed to you is kept confidential. Your test results are not shared with anyone but you. If heterozygous splits (O/o) are found to be in your purebred blue egg layer flock, it is your decision whether to remove them or keep them there. If you choose to remove split (O/o) individuals and only breed with tested homozygous (O/O) birds, you will need to advertise this yourself since your genetic test results are not shared publicly.

Should I Notify Hatcheries or Breeders?

If you find there are heterozygous (O/o) individuals in purebred flocks expected to be homozygous for the blue egg gene, it is okay to kindly and gently notify the breeder or hatchery. The majority of the time a commercial hatchery is at the root of the issue. Fresh breeding stock must be brought in to refresh genetic lines on all farms to avoid inbreeding or line breeding for too long. Many of these fresh birds come from hatcheries and some from other breeders. While it was assumed the hatcheries had invested in genetic testing in the past, current testing is revealing that is not the case. Likewise, genetic testing was so expensive before 2025 that it was not regularly done on small farms.

Breeders have invested a lot of time and money into their breeding stock, which they believed to be fully homozygous (O/O) and which they have been improving by carefully selecting for the bluest eggs. Genetic testing is revealing a few split (O/o) individuals exist in EVERY SINGLE BREED. Since you have paid for genetic testing, your results have value and gently notifying the breeder of ALL the test results (the O/O and the O/o) is okay to do. Most breeders won’t have any idea there was a split in their flock and will be stunned by the news, especially since many of these flocks have over a thousand dollars invested in them. Be as kind as you can, it’s a shock to us all.

What To Do With Split Birds?

Sadly, it is best for these birds to be stripped of their purebred name and sold as Easter Eggers or bred as Easter Eggers only. I know this hurts us today to remove one sweet hen from her flock. But it is the right decision for every generation after for the next hundred years for that breed. If you sell a split (O/o) hen as a “purebred” to another breeder, you only cause further issues for that breed. It is best that we correct mistakes right now, as soon as we discover them.

Easter Egger & Olive Egger Test Results

Easter Eggers and Olive Eggers are NOT expected to be homozygous (O/O). They are very much expected to be split (O/o) and peach or brown layers will all be (o/o). There’s no need to alert breeders or hatcheries since these birds are expected to be heterozygous (O/o) for the blue egg gene if they lay a colored egg. It is possible for homozygous (O/O) Easter Eggers and blue egg layer hybrids to exist, as my test results show for my Spearmint Egger (WTB x Easter Egger) and the Prairie Bluebell Egger (a hybrid).

Homozygous (O/O) Olive Eggers can also exist but they are more rare, around 25% or less of all Olive Egger x Olive Egger offspring hatched. Extremely dark olive egg layers with multiple generations of Marans back-crossing to achieve those deep colors are expected to be (O/o).

Consider Genetic Testing

If you are wanting to breed one of the purebred blue egg layers (Ameraucanas, Cream Legbars, Whiting True Blues) or offer Silverudds (a green egg layer preferred to be homozygous for the blue egg gene) it is worth the price to test your flock! The increased value and easier sales of your hatching eggs generally pays for the cost of testing by the sale of 3 to 4 dozen eggs. This is the best way to ensure we breed better quality birds into the future.

You Might Also Enjoy Reading:

Whiting True Blue Breed Spotlight

26 Chicken Breeds & Hybrids that Lay Blue Eggs

How to Breed Premium Easter Egger Chickens

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