BCM egg genetics question

[PeepingK]

Around 2 months ago my chickens got infected with mycoplasma and I had to cull the entire flock. Since then I’ve decided I’m finally ready to start over again with a fresh batch of BCMs!
I have some experience with the breed but I’m still a little unsure about how the egg colour genetics work.
I found a local breeder who has eggs that are between a 4-6 on the Marans scale but I was hoping for darker. I’m planning on buying hatching eggs from her because she told me that her current hens are around 3 years old so their eggs have lightened up a few shades over the years but that the offspring from those eggs would still lay darker than a 4-6 since the parent stock came from dark lines.
Is this true?

Thanks a ton!

 

[Ridgerunner]

I do not have the dark egg layers so I cannot speak to experience to your specific question. However I do know a bit about brown egg color.

The hen produces a certain amount of brown pigment. What shades of brown are genetic. The raw material is her dead red blood cells. Red blood cells are dying all of the time and are constantly being renewed so it doesn't totally depend on what they eat.

As the eggs get bigger, such as a pullet's eggs start out small and get larger over time, that amount of dark brown pigment has to cover more eggshell. So it appears lighter as the eggs get bigger. This can be fairly noticeable for pullet eggs. The brown pigment is laid on after the eggshell is completed so it only covers the outside. You can think similar to a car going through a spray station.

As you get later in the egg laying cycle the shade gradually gets lighter. By egg laying cycle I mean from the first egg after the molt until the last egg before the nest molt. It's not just that the eggs are getting larger, though even mature hens can have the eggs get a slight bit bigger during the laying season, but the amount of brown pigment seems to shrink. Eggs get noticeably lighter as they get close to the end of that egg laying cycle. I'm not sure why. I don't think it is because they have less raw material but it can and usually does happen.

The darkest eggs you should see are the first eggs a pullet lays as long as her internal egg making factory is working properly. It may take a few days to the glitches out though most do pretty well from the start. The first eggs laid after a molt are generally really dark. So I could believe the breeder's statement that her eggs are less dark at three years because the eggs are bigger than they once were and maybe even later in the laying cycle. How much lighter I don't know.

The rooster will contribute as much genetics to the shell color as the hen but he doesn't lay eggs so you don't know what he will contribute. About the best you can do is to look at the egg he hatched out of when you start selecting which chickens get to breed.

There are a lot of different genes that affect the brown color. Some are dominant, some recessive. They might be partially dominant or may act only if another specific gene is present. One can bleach out brown. One is even sex linked, a pullet can only get it from her father, not her mother. Let's say it can get complicated. How they go together can be pretty random but often there aren't that many different ones present. Your best bet to get darker egg layers is to hatch your darkest eggs and use those chicks to breed.

 

[wrathsfarm]

I agree with @Ridgerunner (and that was a fantastic post btw) that the breeder is accurate.
I've been told to document my first 20-30 eggs laid from my Black Coppers to get an average of egg color expectation. Altho, I do have an odd experience of one of my pullets that hatched in June '23, started laying in Dec, but within the last few weeks her eggs have got darker. Maybe an anomaly, but a very nice surprise....
I'm working towards breeding to SOP and darker eggs also.
I just hatched 8 more Easter Sunday from 3 of my 9 hens....2 from my darkest layers and 1 is a test mate from my all black hen to my slightly over colored roo (should produce proper progeny)

We have a very active Marans thread here I frequent if you want to check that out, it has a ton of great info and pics related to all things Marans.

https://www.backyardchickens.com/th...-thread-breeding-to-the-sop.1122465/page-2383

Best of luck with your Marans...

 

[PeepingK]

I do not have the dark egg layers so I cannot speak to experience to your specific question. However I do know a bit about brown egg color.

The hen produces a certain amount of brown pigment. What shades of brown are genetic. The raw material is her dead red blood cells. Red blood cells are dying all of the time and are constantly being renewed so it doesn't totally depend on what they eat.

As the eggs get bigger, such as a pullet's eggs start out small and get larger over time, that amount of dark brown pigment has to cover more eggshell. So it appears lighter as the eggs get bigger. This can be fairly noticeable for pullet eggs. The brown pigment is laid on after the eggshell is completed so it only covers the outside. You can think similar to a car going through a spray station.

As you get later in the egg laying cycle the shade gradually gets lighter. By egg laying cycle I mean from the first egg after the molt until the last egg before the nest molt. It's not just that the eggs are getting larger, though even mature hens can have the eggs get a slight bit bigger during the laying season, but the amount of brown pigment seems to shrink. Eggs get noticeably lighter as they get close to the end of that egg laying cycle. I'm not sure why. I don't think it is because they have less raw material but it can and usually does happen.

The darkest eggs you should see are the first eggs a pullet lays as long as her internal egg making factory is working properly. It may take a few days to the glitches out though most do pretty well from the start. The first eggs laid after a molt are generally really dark. So I could believe the breeder's statement that her eggs are less dark at three years because the eggs are bigger than they once were and maybe even later in the laying cycle. How much lighter I don't know.

The rooster will contribute as much genetics to the shell color as the hen but he doesn't lay eggs so you don't know what he will contribute. About the best you can do is to look at the egg he hatched out of when you start selecting which chickens get to breed.

There are a lot of different genes that affect the brown color. Some are dominant, some recessive. They might be partially dominant or may act only if another specific gene is present. One can bleach out brown. One is even sex linked, a pullet can only get it from her father, not her mother. Let's say it can get complicated. How they go together can be pretty random but often there aren't that many different ones present. Your best bet to get darker egg layers is to hatch your darkest eggs and use those chicks to breed.

Thanks so much for all that info, it was very helpful!
I just wanted to make sure that the dark egg genetics would get passed on even if the current eggs from the hens are lighter than what they were a couple years ago.
Anyhow, thank you again!

 

[PeepingK]

I agree with @Ridgerunner (and that was a fantastic post btw) that the breeder is accurate.
I've been told to document my first 20-30 eggs laid from my Black Coppers to get an average of egg color expectation. Altho, I do have an odd experience of one of my pullets that hatched in June '23, started laying in Dec, but within the last few weeks her eggs have got darker. Maybe an anomaly, but a very nice surprise....
I'm working towards breeding to SOP and darker eggs also.
I just hatched 8 more Easter Sunday from 3 of my 9 hens....2 from my darkest layers and 1 is a test mate from my all black hen to my slightly over colored roo (should produce proper progeny)

We have a very active Marans thread here I frequent if you want to check that out, it has a ton of great info and pics related to all things Marans.

https://www.backyardchickens.com/th...-thread-breeding-to-the-sop.1122465/page-2383

Best of luck with your Marans...

Thank you!

 

[wrathsfarm]

Thank you!

You're welcome