Not all pure Cuckoo Marans will necessarily lay lovely dark brown eggs, though they really should lay a better coloured egg than a normal tinted egg layer
Often it is the strain which is the most important. What has the breeder (if they are good and knowledgeable breeders) been breeding for. If they are looking to win prizes with their birds at the major shows then the colour eggs their birds produce will be of little or no importance to them and they will be putting all their efforts into breeding birds with correctly coloured feathers and the right amount of points on the comb
If you want Marans which lay dark brown eggs then go to a breeder who is concentrating on this quality, and ask if you can see the general colour and quality of eggs his flock produces. Also check whether they are breeding purely for egg colour in which case you may find you have birds which lay you very infrequent eggs.
Breeding good Marans is a tricky and time consuming project......as I always used to say ..... if it was that easy you would be able to pick up a box of half a doz at the supermarket.
You can look at my website
www.darkbrowneggs.info for lots of info or go to the Marans Club website
www.themaransclub.co.uk It would be good if a few people would join the club and help take the breed forward, it deserves it and needs some help at present. And there is a huge latent demand for quality stock and hatching eggs.