Frank Reese posted this photo of a Cornish-Rock cross from 1968, to compare it with the current version.
Cornish are a valued heritage breed. there's nothing wrong with crossing them with Rocks to get a faster growing bird, but the industrial emphasis on bottom lines has thrown the system out of whack. The birds raised so rapidly -- they are slaughtered at 6-7 weeks of age -- don't develop flavor and their living conditions are horrible.
Check for humanely raised heritage breed chickens at your local farmers' market. I'm fortunate to have a local breeder who raises chickens, ducks and turkeys. I've had her turkeys for the past two Thanksgivings and they were delicious. I'm looking forward to a duck from her.
Her products are always in more demand than she can meet. Industrial chicken piles up. I'd rather have one good chicken than industrial chicken every day.