APPLE CIDER VINEGAR, is fantastic. I was never completely sure about this fact until recently. I’ve always done the – PUT HALF CUP FULL IN 5 LITRE DRINKER ONCE A MONTH FOR 3 DAYS. Seems to work and I do recommend that to people. But this year I’ve used it in the drinking water for day old chicks onwards. A capful in a small mushroom drinker. No Coxy so far (touch wood) no weird fatalities, just healthy chicks. No Mean Feat. I have a brinsea 190, plus 3 basic 50 egg incubators and a Rcom 20 so the volume is moderately high for just a tiny concern. ANYWAY I’M IMPRESSED and will keep using it in chick water.