We presume the above. it could be someone just doesn't realize they should be putting "French" in front of the names of their feather legged Birds . always ask the seller if they're Featherlegged
the difference is cultural. in France, they pasture their Marans, so feather legs are not a problem on pasture. in England , they yard their Marans in poultry yards. the feathers get wet and muddy and are a problem. so they breed their Marans without feathers on their legs.
personally I had my birds and I like the English Marans. because the Marans is originally a swamp bird and it seems to me only gentrification of the breed would put feather legs on such a bird. however, there was a big fight in the breed when it came time to get the Marans approved by the APA . the people who wanted "country of origin" Hallmarks (French) won out and the APA put a requirement for feathered legs in the breed...if you wanted to have them APA approved or show them in APA shows. personally, I think it should have been optional . However, nobody in authority asked me, so there you have it.
Best ,
Karen