Ok I always heard that fast feathering would mean Pullet, is that kinda what your saying? Take a look at my 9 day olds feathering using your theory and let me know what you think???Look at the wing feather growth. If it looks pretty even with primary feathers just a little longer than secondary then most likely a girly. If the wing feathering looks stunted (compared to body size) with the primary much longer than the secondary then most likely a boy. Im pretty sure is a girl: Im pretty sure is boy: Girls look feather heavy in the wing compared to boys.