In the US, there are only bantams, although periodically you will hear about someone working on a large fowl silkie project. There is an active thread on here about largefowl silkies, and the photos show pretty large birds. That said, if you are in the US, unless specifically advertised as such, they will be bantams. In Europe, England, Australia, New Zealand (etc.) there are both large fowl silkies and bantams. Their bantams are a bit smaller than ours.