How old will the birds be?
Barred Rocks should be easy,,,,if the birds are 3 months you shoul do ok.
In Barred Rocks the females are darker than the males by a good margin as soon as they get their feathers,,,,,get more advice than mine. And the females have the darker legs,,,,,,you will know when you see one of each sex standing together because it is that much of a difference. Maybe some people can post pics.
Most roosters will have a tail growing by 3 months but 2 months would probably be too soon to know. If you want other breeds go for 3 month olds and get the ladys by their tails.
I have 2-3 week old rirs and I THINK I have one of each but dont know,,,,one's tail is coming in very very black(boy?) and the other's tail is coming in with some red in it(girl?),,,,,,but these are show rirs. Also the one with the darker tail has a more angular head, but I am only guessing.
Girl Salmons are always cream colored. Wyandottes I dont know.