The absolute easiest was is to fork over roughly $20 and send in a feather for DNA testing. Here is one of the places that does it. http://www.avianbiotech.com/ Its the absolute only guaranteed way to do it. Comb size doesn't always carry through. In different lines of silkies, it can vary greatly. Ex....even on my black girls they might get a comb almost as big as some of my white males. You will see some very large boned, husky, dominant acting pullets as well. I've seen some pullets squeak out a crow and then lay an egg too. If you want a definite answer now, pay for the DNA testing. Otherwise just sit back and be patient for possibly up to a year.