Found this today - which chick

[aart]

Speckledy is usually a Rhode Island Red hen crossed with a Cuckoo Marans rooster. The Bluebell is a Rhode Island Red and Blue Copper Marans cross.

Ah, I see......didn't read those details....but didn't look too hard either.

 

[rebrascora]

I think it is more likely that your Black Rock is actually a Black Copper Marans and she laid the dark brown egg. My BCMs are currently laying that colour. I don't have experience of Speckledys but Bluebells lay a pale brown egg. Where did you get your chickens from? Was it sold as a Black Rock? Did they also sell Marans?