How old is she? They stop growing around 5-6 months old. As far as actual Silkie size, it can vary from orgin. A lot of places refer to them as bantams due to them being too small to be a standard, even though they aren't bantams. Most of the Silkies in the US are about twice as large as your average bantam while Silkies from China or Japan are more closer in size to standard chickens. Now these are bred true Silkies, not hatchery Silkies, particularly Silkies from TSC. TSC are closer to standards with many of them not showing pure qualities (missing toes, feathers on shanks, crests, wrong combs, etc.).