Good for you. I'm glad you practice biosecurity with an infected flock. I think you're the first person I've read that practices it.I had that happen with my flock. I had one tested and it was positive for MG. Now my flock is closed. No ones allowed to come here without spraying off thier shoes, washing thier hands before and after leaving. I carry a spray bottle of Oxine in my vehicles if Im going to get feed and have dedicated shoes for that and ones for just the barn. I disinfect thier buckets once a week with Oxine or bleach.