Last year, all of my chicks got PB. This year I kept a humidifier going in the room with them and only about half of them did. I don't use ACV, just plain water, except I did give them probiotics in their water on about Day 5. I follow Eggcessive's advice on the temps. For those with PB, I washed their bottoms with warm soapy water (a few drops of Dawn), rinsed and dried with a soft paper towel. Those that were really poopy and therefore quite wet got blow-dried. A few needed repeat treatments, but fewer each day for a few days. All were clear by about 10 days, I think. I wear Nitrile gloves for the procedure.