The following paragraphs are taken from an excellent French site http://marans.cyberscope.fr
The town of MARANS is an Atlantic port, about twelve miles north of LA ROCHELLE, at the mouth of the river Sevre and the canal system that forms the famous MARAIS POITEVIN, more often known as the GREEN VENICE. Fens rich in gray clay, bathed in hot sunshine during the day but sleeping under a thick blanket of mist at night, surround the town.
It's in these immense expanses, often covered with briny water during the winter high tides, that on the raised ground could be found these courageous farmers cultivating their modest lands. Linked to their capital MARANS, by the canals where small flat bottomed punts offer the sole means of transport, not only for themselves but also for the many itinerant trades people
Since Roman times, MARANS has been a port specialized in cereals that arrived mainly by river or canal from the surrounding regions. This favored the development of poultry farming with a local breed of chicken known as the PICTAVE.
These early attempts at breeding were well supported by the many monasteries that were established in the area, monasteries detaining certain privileges for the utilization of cereals, and a large population of monks maintaining a constant demand for eggs and chicken. The local farmers were breeding then a small black chicken that was the popular in the Aunis and Vendee fen regions.
In the XIIth century, and during nearly two centuries of occupation, the English conquerors began using the port of MARANS to export cereals, wines from Cognac, and the poultry from MARANS; a trade with ENGLAND that thrived, almost uninterrupted, for more than eight centuries.
In order to have fresh meat and eggs constantly available, ships have always carried live chicken on their voyages. The English ships sailing into MARANS were not an exception, especially as during calms and when "off-watch", the English sailors were particularly fond of cock-fighting. The hens and fighting cocks that remained alive at the end of the voyage were put ashore to be replaced by fresh birds. It was in this manner that the hens of MARANS made acquaintance with the famous English fighting cocks, and the region became the birthplace of a particular breed of poultry, originally known as the MARANDAISE, later to become the MARANS.
However, it was not until 1880 that the MARANS started to appreciate a widespread reputation, due largely to the rivalry between two brothers, both poultry merchants in London. One of them was one of the biggest wholesalers of white Russian eggs, then the most important poultry producing country in Europe. His brother, whose ships often docked at MARANS, had the idea of competing with the white Russian egg trade by selling the dark brown eggs of MARANS, bigger and fresher.
History of Marans - Compehensive article on the history of the Marans breed (slow to download so be patient)
Useful links for Keeping Marans
http://marans.cyberscope.fr Excellent French site with information available in English
http://marans.eu/ Another very informative French site, with lots of pictures and information also available in English translation
Help and information on keeping chickens and other poultry at home. There is a helpful chat forum for questions etc