Marans are French and if bred to the French Standard should just be called Marans, not French Marans.
The ones bred to the English Standard have clean legs.
Belgian bantams definitely have the worst names. 🥲
Not any different from dog breeds, really. The way I learned was checking out Storey’s Guide to Poultry Breeds from the library. It’s a bit outdated but back when I read it it was fairly recent. Also some of the pictures aren’t good examples of their breeds but at the time I didn’t know any better.