Actually, with EE's white/silver (with black patterning) is most frequently male, while the wild type is frequently female, however brown/dark will not tell you which ones will become the typical partridge female pattern and can produce plenty of dark colored males while the light pattern, in particular white, is not often female.
There is some research that shows in wild type (chipmunk chicks), those chicks with 3 color bands (ie a brown bar between white and black stripes) that run from the top of the head down the neck all the way to the tail are usually female while the male pattern is usually 2 band colors (just the brown and black or brown with white) with an interruption at the neckline....head spot, nothing on the neck, then continues down the back.
But unfortunately there are too many exceptions to make this a sure thing...but I have found it to increase my odds.
If you are picking out older birds again, always choose one with the small, pale comb, and peas (much more likely to lay the colored blue/green egg for you) and with an even feather pattern....think kaleidoscope rather than patchwork quilt. The females will have regular even patterning while the males will have blotchy coloring...never chose a bird with red bars on the wing bows...that will be a rooster.
Good luck on the exchange.
A good article on sexing chicks:
Exactly. There are no hard and fast rules for Easter Eggers. Of my 3 Easter Egger chicks, one was male.
He's in the very back of this picture.
He's the one in the middle here.
You can not tell, with any certainty, what an Easter Egger will look like as an adult based on their chick down.
While quite a majority of the silver based birds are male, there are far too many that turn out to be females for it to be a 'rule.' Likewise, there are too many red-based/partridge type males to say that all red/gold birds are/will be female.
Mine turned out to be a red-based columbian pattern.