ModernGames, you could try contacting the farm and seeing what kind of chickens they use. My guess based on another egg farm is they do use sex linked for the layers. They will probably put roos of a different color in with them. So they may use ISA Browns for hens and then white roos like Legherns or New Hampshire Whites so that when they look out at the ginormous flock they can tell at a glance which are roos and which are hens. Just an educated guess on my part, of course.
I think if you put white roo over sex linked you get an even mix of red and white babies and they are no longer sex linked so there is a mix of boys and girls between the colors. Perhaps someone that is an expert in genetics will confirm or correct my statement.
Super cute babies!