bobbi-j, I had a batch of Dark Cornish from Ideal last year. I got 4 hens and an Oops cockerel. I got them as I wanted broody hens and to add some meatiness to my mixed breed birds.
Only one hen went broody. It was while I was gone and she hatched out a dozen chicks. Barn cat got 3 before I realized they were vanishing. I sold one pullet, butchered the cockerels and have three pullets who are showing absolutely no signs of laying any time soon. They were hatched in early-mid June. The father of the chicks was a splash Ameraucana, so the cross wasn't great for either production or meat. I'd hoped the cockerels would have some more weight to them, but the carcass was indistinguishable from my other Ameraucana crosses.
The Oops rooster was a joy to be around, nice and calm and good to the hens. The hens were not flighty, but they sure seemed to eat a ton for how many eggs I got. I decided not to go for the added weight in my next generation so I sold the birds to some 4-Hers who fell in love with them
. Would I get Dark Cornish again? Not with my current goals. I did wonder how the rooster would have done over say some Wyandotte hens, something fairly meaty to start with. Since you're wanting more weight on your birds, that may be a way to go for you. I don't know why mine weren't as broody as they're reported to be, but then again I was gone from home quite a bit while I had those birds, so maybe they didn't get a fair evaluation.