My cornies aren't mature enough to lay eggs. I do have one cornie, that from the beginning, separated herself from her siblings, and wouldn't gorge. She hangs out with the leghorns.
Having the mixture of all three types of birds, I can harvest when I want from all three groups. A normal...
From talking to others, lots of research, and personal experience, I category chickens into three groups - layers, meat birds/dual purpose birds, and broilers.
Layers would be the chickens that don't get big and heavy and are prolific egg layers - like Leghorns.
Meat birds/dual purpose birds...