I say raise them how you want. Like you said not many of us have chickens that actually ever see a vet. If not for the USDA Vet inspecting me, mine never would see one.
The FF feed is issue becomes so personal and finding any reliable information that is not anecdotal is nearly impossible. It tears threads apart so I prefer we just talk about what keeps us together,,,Turkeys..
I don't do FF for the simple reason is that it would create a lot of work for me and also is not a natural way for poultry to get their food. I keep feed and water in front of all my poultry at all times. My main feeder holds 150 lbs. of feed. I did the same when I raised CX and BBWs. I did not have any leg issues but my poultry gets lots of exercise whether it is from free ranging or just spending time in a 50' x 100' run.