I have a working theory going on Silkies. The boys tend to have a defined straight line from the start of their tail poof. The girls tend to arch up toward their mid back when looking directly over them. I have been 100% accurate with birds 4mo and older.
The rooster that fathered this splash had a really nice, round cushion. He was very girly. His comb was very small. I'm still leaning towards pullet too, but figured I'd check. I REALLY need a nice boy, I haven't hatched many cockerels this year and right now I am roo-less