I understand what you are saying. Get better pics of the faces of the off color poults. Your Blue Slate hen, based on her appearance is BB Dd. For those poults to be hers, they need to have the white face mask associated with the black color gene. She does not have the bronze color gene or the black winged bronze color gene which is needed to make those poults hers. If she had either of those genes, her wing feathers would be barred. Your photos do not show any barring.The bronze hen was from a bronze/royal palm.
The babies have to be from the slate; as the bronze hen had her own nest in our neighbors yard.
I only have a bronze tom; I was trying to explain where the hens came from. I am friends with the lady I got them from and her only tom was a royal palm.
I know my hens will lay eggs in each other's nests until one of them decides to go broody. At that time the others will find a new nest to lay eggs in.