Summary A free‐range broiler breeder flock was studied in order to determine the natural patterns of C ampylobacter colonization over a period of 63 weeks. C ampylobacter sequence types ( STs ) were not mutually exclusive and on average colonized only 17.7% of the birds tested at any time. C ampylobacter STs typically reached a peak in prevalence upon initial detection in the flock before tailing off, although the ST and antig...