Dark Cornish are great eating birds all on their own. I cross them for a better rate of gain/faster growing bird. I also like a lighter feathered bird for plucking.
Here are a few of my Dark Cornish/ CX cross birds:
Pure Dark Cornish (4 months)
50% Dark Cornish 50% CX (3...
I used Murray McMurray's Cornish Roasters - slower growing. My birds grow faster than heritage Dark Cornish, but slower than The CX type. The group meat pics are birds taken at Cornish game hen size ~2 pounds dressed weight. My 50%DC / 50%CX birds usually attain weight by 4 to 5 weeks. I like...
Good luck with your project. I use Dark Cornish over a CX hen. I also use a high protein starter. You are on the right track. Your birds look good. I have to use vitamins in the water. Meat birds grow fast and at times they grow unevenly. Too much stress on the bone to muscle without a vitamin...