Impossible to tell from this vantage point. Could be a dark cuckoo. Need a side profile. Marans is always spelled with an "s" , either singular or plural. When the bird starts to lay the egs have to be a "4" or better on the French egg color chart to be considered a Marans, even if the bird is genetically from Marans stock.
I'm just not sure of the breed. I got them the last week of February from the farm store. I have 10 chickens. 3 Rhode Island reds, 2 buff orpingtons, 2 white leghorns, a black australorpe, and the last 2 (i think) are wellsummer and Maran. But I'm not sure. My friend picked them out.