I have: 10 EE, 10 leghorns, 10 light brahmas, 10 red sex links, 10 barred rock, 11 silkies, 8 guineas. Except for the sex links, which are all supposed to be pullets, and the guineas, which I'm supposed to be able to tell the sex by their call, how and when should I be able to tell the "girls" from the "boys"??? They are 4 wks old tomorrow.