Broiler farming practices using new or re-used bedding, inclusive of free-range, have no impact on levels, species diversity, community profiles and bacteriophages.

A multi-stage option to address food-safety can be produced by a clearer understanding of 's persistence through the broiler production chain, its environmental niche and its interaction with bacteriophages. This study addressed levels, species, genotype, bacteriophage composition/ levels in caeca, litter, soil and carcasses across commercial broiler farming practices to inform on-farm management, including interventions. Broilers were sequentially collected as per company slaughter schedules over two-years from 17 farms, which represented four commercially adopted farming practices, prior to the final bird removal (days 39-53). The practices were conventional full clean-out, conventional litter re-use, free-range-full cleanout and free-range-litter re-use. Caeca, litter and soil collected on-farm, and representative carcases collected at the processing plant, were tested for levels, species dominance and bacteriophages. General community profiling via denaturing gradient gel electrophoresis of the gene was used to establish the population relationships between various farming practices on representative isolates. The farming practice choices did not influence the high caeca levels (log 7.5 to log 8.5 CFU/g), the carcass levels (log 2.5 to log 3.2 CFU/carcass), the / dominance and the on-farm bacteriophage presence/levels. A principal coordinate analysis of the distribution for farm and litter practices showed strong separation but no obvious farming practice related grouping of . Bacteriophages originated from select farms, were not practice-dependent, and were detected in the environment (litter) only if present in the birds (caeca). This multifaceted study showed no influence of farming practices on on-farm dynamics. The significance of this study means that a unified on-farm risk-management could be adopted irrespective of commercial practice choices to collectively address caeca levels, as well as the potential to include bacteriophage biocontrol. The impact of this study means that there are no constraints in re-using bedding or adopting free-range farming, thus contributing to environmentally sustainable (re-use) and emerging (free-range) broiler farming choices.