For Sultans, LC only counts standard fowl. Unless they are true bantams, with no large fowl counterpart, bantam birds aren't included, because they've been crossed with other breeds to size them down. Single birds, or female-only flock birds are not included, either, because they are not contributing to the breeding program and will not help keep the breed alive.
If you go to the site, you can see a sample of their poultry census. It's very comprehensive. There's even a breakdown that shows how many of the official count are in the hands of commercial hatcheries and how many are in private, backyard breeding programs.
https://livestockconservancy.org/index.php/heritage/internal/north-american-poultry-census