I have a problem with Mariks disease after I purchased 12 week old deathlayer pullets. Almost a year later I am still loosing some unvaccinated birds and I lost one vaccinated bird. So I vaccinated my whole flock at home. I boosterd already vaccinated birds, Unvaccinated birds that have been exposed to my flock, chicks and grow outs from my clean rooms. even the turkeys. I also vaccinated one slightly symptomatic, hen( standing on one leg, stopped laying, isolating herslf from the flock.) It's been 4 days and no side effects. The real suprise is the symptomatic hen is dramatically better. Has anyone ever vaccinated adult , exposed or symtomatic birds with positive results?