| brachyspira intermedia and brachyspira pilosicoli are commonly found in older laying flocks in pennsylvania. | anaerobic intestinal spirochetes (genus brachyspira) include several species that are recognized as pathogens of poultry. surveys undertaken in europe and australia have shown that layer and breeder flocks are often colonized by the pathogenic species brachyspira intermedia and brachyspira pilosicoli, but similar surveys have not been conducted in the united states. in the current study, dna was extracted from fecal samples (n=50) collected from each of 21 flocks of laying hens >40 wk of age in ... | 2009 | 20095153 |