Important Findings This report describes outbreaks of histomonosis, a severe disease caused by the protozoan parasite Histomonas meleagridis, which occurred over a period of 3 yr on an organic farm in southern Germany. Among other species, the farm houses layers, broilers, and turkeys. Genotyping of the histomonal strains causing the disease showed that at least two different histomonal strains caused the outbreaks and that the strains circulated on the farm at the same time.