Turkeys will bond with any species they are raised with and will see no difference between themselves and the other species. This can turn into a mess with the turkeys trying to interact with the other species as if they are the same. I've had chicken bonded turkeys kill a rooster. I personally would never raise them together past the 8 week mark. I would separate out you silkies ASAP.
Some silkies are pretty big. I've seen some on this site as big as standard breeds. The higher protein feed will make chickens mature earlier but that isn't always a good thing. You want slow steady growth and you don't want pullets maturing too early as they can have problems laying if they aren't fully mature yet. Even the turkeys should be fed a lower protein as they mature. Generally at a month they should be getting around 24% protein, and at 2 months and beyond it's 18%.