All chickens raised for meat are raised cage-free. All broilers are raised in a barn environment.
With regard to egg production, when you say that free-run environment presents challenges as well, of course it does. Every production system presents welfare challenges, but the inherent thing is that when you put an animal in a cage, the challenge is that the welfare problems that environment raises just cannot be solved in that environment, because they're inherent to a cage environment, as opposed to welfare issues in a free-range environment or a free-run environment, which can be handled by good management.