Aww! Mine dropped his crown about a month ago, He is about a quarter of the size it was... but doing wonderful! After he dropped his crown, it dissappeared quite quickly, and now, have itty bitty feathers everywhere.
From what I have researched they won't get any bigger. My biggest one started about the size of a pin on the glass, and is now about the size of a pencil eraser. Ther are neat...but causing me to not be able to clean the glass around them...they might be gone soon, the glass is getting pretty bad.