okey thanks, maybe I should just allow my old rooster to live for little bit longer and let him mate with my new hens, that way I would choose hens that lay dark eggs and then get rooster from them, that way I wouldn't be using brother and sister but a mother and son (saw that was okey to use mother and son and someone mentioned that here also in the first comment).
or I could take a rooster from the egg that are in the incubator now that are from my only cuckoo maran hen, that are only 4 eggs from her there so I will probably get weary few hens, haha
but that way he would be only related to his mom and yes if I would get a hen he would be related to her to but I would just not use him with that hen, he would of cause be a mix tho because his mom is a mix but she lays dark eggs and his dad is a purbreed and I'm only using this breed for myself, I'm not selling chicks or anything so maybe it would be okey
these information have been really help full to me and now I will just decide what to do, maybe I fall in love with some rooster that comes from the eggs from my hen, the eggs from my hen should hatch out after 12 days, I'm so exited
Visit the marans of America website and click their 2 pen spiral breeding program. If you follow their plan after 5 generations of a inbreeding there will only be 16% inbred. This is for breeding chickens to a closer SOP, don't know if it is applicable to eggs shell color.