There is a thread here called, Fermenting Feed for Meat Birds. I've done a one bucket, hot water method. No ACV needed. Just put your regular feed in a bucket, add hot water, stir, cover loosely. Should be like a thick soup. Feed expands as it absorbs the water. Ready to feed your birds by the next day.
Just keep adding to it daily, feed & hot water. Other benefits include better shell quality & better absorption of nutrients. Others may experience even more benefits, but these are a few I feel I've experienced.