I bought 2 black silkies from a woman who was kind enough to tell me she had a breakout of blackhead in her flocks. The chickens were treated and have been isolated for months from my other chickens because I am afraid to put them anywhere near my turkeys. My question is , Are they cleared of it completely? Or do they carry it forever? I can treat with Valbazen if needed for a second dose. They have literally been isolated for MONTHS( and have never been on the ground with my other birds) but had the initial treatment right after I bought them.( they were only a couple of weeks old when I bought them and the hen JUST started laying last week.)to give you an idea of how long it has been. Was one treatment enough to cure? Or should I never let them around my other birds? Thanks for any help... Oh, and is it safe to hatch eggs from her? Or should I just cull?? Anyone?