Same as the Coin on a string method which is wives tale, & doesn't work.
Stance isn't always a good indicator of gender with silkies, I've had both males, & females stand tall. Same with other breeds I have.
Females will start fights too. It's not a gender specific trait.
Tail feather length...
Lynching by the neck to tell gender of a chick isn't a good idea either, & it doesn't work.
Pullets can have very outgoing personalities too, & I don't sex based on observation due to that.