I have two Welsummer hens that had bumblefoot off and on for about a year and a half. It was a constant battle, it would clear up for a month or so and bam, one would start limping and sure enough, the bumblefoot was back. Sometimes it would strike both feet at once. I tried epsom salt soaks, drawing salves, rounds of antibiotics, numerous surgeries performed,by a vet which was expensive, not to mention very hard on the girls. On the advice of the vet, I needed to cover the roosts - sanded 2 x 4 boards - with something to change the pressure on their feet. I used the nonslip bath mats that go inside the tub that "massage" your feet with different size bumps. I cut them into strips and stapled them to the roost bars. The only other change was I switched from Layena to Organic Blue Seal layer pellets and I have not had a single incident of bumblefoot in 15 months!! Of all the advice I read about bumblefoot prevention, I never saw anything about changing the surface of the roost but it has worked like a charm for me and my girls. My vet in in Raleigh, NC and if anyone wants his name, please PM me.