I bought Cornish X's as my first ever chicks at
Tractor Supply, not knowing any better. I couldn't figure out why they didn't roost or even go up the ramp. Sadly I found out about them being bred as huge eating machines to be slaughtered at a young age. I haven't even eaten birds in ten years and I was so upset that I inadvertently contributed to that industry of factory farming I try to avoid.
My 2 cockerels had to be euthanized at 1-2 months of age. Both of them had maggots, I guess from messy butt or dragging on the ground. I tried hard to keep them clean to no avail.
My 4 ladies fared a little better, avoiding the maggot fate, but succumbing to the heart problems anywhere from 8-19 months old. They all were encouraged to free range and get exercise and work for their food. Boy was it comical when they would come running for treats! One did seem to have slight leg problems but it wasn't even the biggest one. They all weighed between 15-17 lbs.
Some say it's cruel to keep them alive longer than 2 months. I personally disagree. My birds seemed happy to greet each day and do whatever they could. They didn't seem to be aware to me of their disabilities. That's one of the things I like about having birds-they wake up excited every day to get on with the business of bird living and they take life as it comes. They don't seem to worry about the future.
Of course people keep birds for different reasons and I don't hold it against people for raising animals for meat, so long as the animals' lives and deaths are as humane as possible. My Cornish X laid huge delicious eggs about 4 times a week, sometimes double yolks, and often ones that were so big I thought they'd be double or triples, but they were singles. You've heard of pullet bullets? These were pullet torpedos!