We bought them as chicks, they are 6 weeks old, supposedly. We bought them, not thinking to make sure they were hens, we called and asked....they told us they were straight run, so who knows what they are. Any guesses??
I'm gonna go against the aboves and say red sex links. At six weeks my cornish cross were much larger and squatter and had much smaller combs. I think your brown bird is your hen, she'll be a great layer of large brown eggs. I think all the white ones are roosters, they will get more red in the wings as they age. They'll be great eating at five months or so.