Seems my Cornish Xs are heavy. I went out and weighed a few. 9-12 pounds each. They are 8 or so weeks old. Seems I read alot about peoples meaties being lazy and joint issues. Mine run around like the rest of the birds. They might waddle a bit more but dont seem to have any issues running or walking. Now they do come at you like a fat kid chasing a twinky. They are by far the friendliest birds ive got and will come up and talk to you. Only problem I see is a lack of feathers between there legs back towards their vents. I would assume its because they stay on the coop floor and don't perch like the others.