Dark brown eggs

[Ponte]

Last week one of my BO began laying dark brown eggs once-twice per week, on her other days The eggs are beige. I assume they are perfectly fine but wondering what explains the dark brown shells.

 

[oldhenlikesdogs]

Do you have a picture of the hen? Pure buff Orpingtons won't lay eggs that dark.

 

[Ponte]

Have three, they look very similar to each other. So similar that my three kids and wife cannot tell them apart. Would be surprised if they are pure BO.

What is interesting to me is that four days a week she has beige eggs and twice a week she has dark brown eggs.

 

[oldhenlikesdogs]

She looks pure. Are you sure she's laying that egg? I've never seen one like that out of a buff Orpington, or any other color of an Orpington.

 

[Ponte]

She looks pure. Are you sure she's laying that egg? I've never seen one like that out of a buff Orpington, or any other color of an Orpington.

Am sure.
I have a SS which lays a bone-beige color egg, the EE lays green color egg, one BO lays a speckled beige egg, another BO lays a beige-pink egg and the one I am asking about varies from dark brown to beige.
I and the kids are often in the yard and have never seen a chicken wander in. The only other person in the area with chickens is two blocks away and they have a closed in run.

 

[oldhenlikesdogs]

It must just be what she does than. Varying factors can affect pigment distribution on an egg. Sometimes there's glitches that eventually resolve. If it continues than it's just what she does.

 

[Ponte]

I find this very interesting.
Would you know a good source to read on egg pigmentation?

 

[oldhenlikesdogs]

https://animals.howstuffworks.com/animal-facts/white-brown-green-chicken-eggs-whats-difference.htm
https://www.abc.net.au/news/2018-02-19/chemistry-of-eggshell-colour/9455660
Color on an egg comes from components of a chickens blood. Things can alter the pigment. Generally it lightens up. I haven't personally seen it darken, except in New layers or hens that have had a rest. Eggs generally start darker and lighten up over the season.

 

[Ted Brown]

This is what I get from some of my ladies. The middle egg is what I would call a normal brown egg, the upper one obviously blue (although I often "see" it as greenish), the bottom is "chocolate" (I "see" it as a dark brown). I also get "chocolates" that are even darker than this.

 

[Ridgerunner]

The basic process is that the egg spends many hours in the shell gland while the hen builds the shell, then the last half hour or so she lays the brown pigment on the surface. If you look on the inside of the shell when you break it and remove that membrane you can see the base shell color.

Most hens make a certain amount of pigment per day. If she lays a really large egg, like a double yolker, the color can be light. If she lays a small egg that pigment can go on thicker since it has less egg to cover so it can be pretty dark. Your darker ones appear to be regular sized so I don't think this is it.

It's unusual for a hen to lay a normal egg that much darker. Most of the time there is a big color change the egg is lighter. It may be a defective (in that regard) shell gland, maybe she is delaying laying it for some reason. As long as she is acting normally and egg shell thickness is normal I would not worry. You have perfectly usable but somewhat unique hen.