I noticed that my 4 chickens (Purina + free range) are younger and started out smaller than the farm chickens, however, the farm chickens now look skinny by comparison.
I was ever so delighted to see that the farm chickens are now out free-ranging. I suppose the farmers decided since my chickens were surviving and thriving, perhaps it is not such a bad practice.
I believe the farm chickens were getting chicken feed. They get tons of fresh veggies from the garden whereas mine really do not. Before free-ranging, the farm chickens were kept on very clean concrete with a variety of perches and shelters.
I wonder how much of a chicken's condition can be attributed to excersize and mental activity.