Culling KOI?

I have about 100 fry well they are about 1 month old now and getting bigger everyday. I am wondering if anyone knows how to cull them? what to look for and such. I have seperated the much larger ones already. I have noticed some have big black eyes and some do not. Any help is appreciated.Thanks

DawnieRee

Everything I have read says that it is to early to tell. Just have to cull by numbers alone.