Yep, I had those last year....didn't know I had them until later. They will always have bald spots because their feathers cannot keep up with their growth rate. Another way to tell is their legs are splayed further apart from each other. They say they should be slaughtered at 8 weeks but I think I did mine at 9 or 10 weeks. I had to pick them up and put them in coop at night and take them out in the morning because the ladder wasn't wide enough for them and I didn't want them to break their legs jumping.. My smallest dressed out at 7 lbs. and my largest dressed out at 8 lbs. They are hard to get to the point of being able to lay eggs but I read up on them and some people have been able to do it. Because I didn't know I had Cornish Rock X, I fed them chick starter. I later tried to feed them other feed but they wouldn't eat it. Finally, I brought the chicken starter back and they stayed on that until I butchered them. Mine were incredibly calm. Of course they were so fat they couldn't run. )))))