I personally have never used medicated food. I've had chickens for five years now, and we did have an episode with cocci one time, with some chicks. I noticed that there was blood in their droppings.
This was during an extremely hot, wet summer and that's the perfect environment for cocci to grow and spread. If that happens, as soon as you see bloody droppings you need to buy Corid, which is a powder advertised for cows, and you add that to their drinking water. You can use Sulmet, but it's harder on their systems.
Bascially, keeping their area as clean as possible and dry, will keep the cocci from invading your flock. Back when we had the cocci, my chicks didn't even seem sickly, because I treated them so quickly. Their run had dirt as the base.
I had to throw bleach over the dirt and not use it for quite some time, until the dirt had totally dried up. Then I put a very thick layer of sand over the dirt. I've never had that problem again.
I do rake my chicken runs almost every day though, I pick up the poo with a kitty litter scoop, or I rake it up, and dispose of it.
I hope this helps and good luck with your meaties,
Sharon