I don't use medicated feed or get my birds vaccinated and have never lost a bird from anything other than dumb luck. It's all a matter of chance while raising your own meat. The best advice I can give is get every opinion you can and pick through to make the plan that is best for you.
With my family is would rather stay chemical free so if on occasion we have a loss due to illness I see it as ok. However I have children with medical problems so I feel adding in extra medication is a bad idea. Hence the home grown foods. You have to do what you feel comfortable with. I see no reason not to use medicated feed other than personal preference. I also see no reason to feed non medicated feed other than preference. I have never lost a bird from illness and I have raised upwards of 200. We eat the eggs and the meat. I stew up the rotten tempered cockerels and old hens who stop laying so again , it's all personal choice.
I have also talked to folks who have lost 200-300 birds from 1 nasty illness or another even though they vaccinated or used medicated feed. On the same note I have known some to never vaccinate and loose and entire flock.
As stated before I'm not a professional poultry farmer, I raise for my family and friends so by no means is what I say the best way to go. Your flock has to be raised how you feel comfortable. There is a saying "an ounce of prevention is worth a pound of cure". That's why I'm feeding chemical free to my family (including the furry 10 and the feathered 152) .
I apologize for the long winded explanation.
No apologies! Thanks! I've only used medicated feed on the last batch of EEs we hatched and I was sorta impressed with the results but not enough to totally convince me to use medicated feed on my first run of meat birds. Plus it's hard to find medicated feed at the right protein level where I live. I've got standard chick medicated feed on hand, so I'm prepared as I can be for whichever way I decide