I knew when I bought these chicks that the chick on the top left in the second picture and second 4 week old in the first picture next to the gold one is a roo. It always was larger and had thicker longer legs than the others. Now it is getting a few rust colored feather coming in at the shoulder area. They are 5 1/2 weeks now. In another week we will see what grows out lol cause I still think its a rooster.