Who laid this egg?

[OrpingtonFairy]

so i got 3 new chickens over the summer. 1 silkie, 1 Polish and 1 lakenvelder. Silkie turned out to be a rooster, and the lakenvelder (which i learned a couple months later) is mixed with an Ameracauna.
Now i thought my lakenvelder mix laid her first egg s month and a half ago. It’s pinky light brown. And my polish has not. But i found an egg that i have no idea who it belongs to. It’s a tiny brown almost dark brown egg. But polish lay white, right?
I have attached a picture with the mysterious egg. Top one is what i think lakenvelder mix laid, second is my Easter egger, the third one down is the mysterious egg! And the last one is my Orpington.
Anyone have any clue to what’s going on?

 

[A.M. Eggs]

Can you post a picture of your Polish? She might be a mix of some kind.

 

[OrpingtonFairy]

Can you post a picture of your Polish? She might be a mix of some kind.

I believe she’s a buff polish

 

[A.M. Eggs]

It's definitely a buff polish. Are there any other hens that you have that lay copper eggs? It could be a "fart egg" from another hen.

 

[OrpingtonFairy]

No. That’s why I’m completely bugged out. I was wondering maybe it just stayed in the ovaduct too long. Since it’s her first egg. I’ve heard they can get much darker that way. I’ll see if her second egg comes out that way.

 

[ve]

what happened to your Marans hen, this egg is very dark.

 

[OrpingtonFairy]

what happened to your Marans hen, this egg is very dark.

A raccoon got to it over a year ago. I haven’t gotten a dark egg since