The chicks outgrew their single pool, so I split them up. I put the laying chicks in one pool and the meat chicks in the other pool. The differences between the two types of chickens is amazing. The cornish rock cross chicks (the yellow ones) have been bred to grow fast and be butchered quickly. They feel hefty when I pick them up. The laying hens feel about one-third the weight and size of them!
You can see a difference in the chicks in how they approach their food. The laying hens in the top picture see their food and are picking at it - they're more concerned about me with the camera - while the meat chicks are a solid block of yellow on top of their feeder.
I tend to slightly underfeed the meat chicks. I find that, if given the chance, they will almost eat themselves to death. By slightly underfeeding them (meaning they don't have food available every minute of the day and night) I find that they don't have the fantastically rapid weight gain and growth that leads to feet and leg problems. These chicks actually grow up and will be able to spend a portion of their lives pecking and running around outside!