Broiler Chicken House Terminal Hygiene for Campylobacter Control

Campylobacter species are probably responsible for more cases of human bacterial gut infections than any other bacterium, and around 70% of global cases can be attributed to poultry in some way (1), usually through consumption or cross-contamination from undercooked chicken meat. This constitutes a huge public health burden, to which the poultry industry is inseparably tied. Government regulation consistently tries to lower Campylobacter counts on fresh chicken products (2), and with factory interventions only able to go so far, there is currently a shift towards on-farm Campylobacter control within the industry. Campylobacter infection can also negatively impact bird welfare and feed conversion ratio (3,4).

Broiler chicken production in the UK typically occurs in cycles, consisting of an overall growing period of 36-40 days and a turnaround time of 7-10 days. During turnaround, the house is cleaned and disinfected prior to the arrival of the next batch of chicks arriving for the successive cycle (5). This procedure is a critical step in ensuring that bacteria, viruses and parasites do not transfer from one flock to the next, and form a fundamental first line of defense for chicken producers to ensure healthy flocks.

While Campylobacter is not a particularly hardy organism in its active form, it can transform into a temporary dormant phase known as ‘viable but non-culturable’, or VBNC. Campylobacter in this form can survive multiple different stresses that would otherwise kill active cells, but cannot reproduce or thrive until they find a suitable host and revert (6,7). VBNC cells are also unable to be detected by conventional laboratory testing through culture of swabs, but are still present and infectious in the poultry house. For these reasons, thorough terminal hygiene regimes should be stressed as vital to prevent the onwards infection of Campylobacter to subsequent flocks to be placed, following a Campylobacter-positive flock (8).

Although methods vary between farms and regions, typical clean-down of a chicken house consists of (5):

• Removing litter and cleaning drinker water lines.
• Washing all surfaces in detergent.
• Washing and disinfecting drinker cups.
• Laying down new litter.
• Final fogging with formalin.

Modifications can be made to this formula to better combat Campylobacter, which can not only reduce bacterial counts but also improve broiler productivity (4).

Campylobacter is particularly susceptible to drying, and experiments on both chicken houses and transport crates have shown that thorough post-disinfection drying of any surfaces that chicken come into contact with has a significant impact on the likelihood of Campylobacter survival (9,10). Therefore, extending turnaround to allow for adequate drying time (11) or employing dehumidification techniques may help in reducing Campylobacter in subsequent flocks.

Although traditional formalin fogging has been used for many decades, there are newer hot-fogging alternatives using other commercially available chemicals that have proven anti-Campylobacter action that formalin does not necessarily have (5,9). This can also help get around the inherent toxicity of formalin and can improve the health of both farm staff and housed birds.

Terminal hygiene should not just be limited to the inside of the poultry house. There is evidence of Campylobacter survival in other reservoirs that can re-infect a house, such as tarmac on the yard outside, vehicles used in the turnaround process, anterooms and personnel (9). Biosecurity principles and clean equipment should therefore still be employed even with no birds present, to better protect them from infection.

Poultry vet practices and consultancy services can help in improving your turnaround routine (5), or can give advice on changes to make to combat the recurrence of particular diseases.

1. Wilson, M. & Wilson, P. J. K. Gastroenteritis Due to Campylobacter. in Close Encounters of the Microbial Kind 439–450 (Springer International Publishing, Cham, 2021). doi:10.1007/978-3-030-56978-5_32.
2. National Archives. Commission Regulation (EU) 2017/1495. legislation.gov.uk : https://www.legislation.gov.uk/eur/2017/1495 (2017).
3. Humphrey, S. et al. Campylobacter jejuni Is Not Merely a Commensal in Commercial Broiler Chickens and Affects Bird Welfare. mBio 5, (2014).
4. de Castro Burbarelli, M. F. et al. Cleaning and disinfection programs against Campylobacter jejuni for broiler chickens: productive performance, microbiological assessment and characterization. Poult Sci 96, 3188–3198 (2017).
5. St David’s Poultry Team. Broiler Turnaround: Resetting Farm Health. St David’s Veterinary Surgeons Ireland https://stdavids-poultryteam.ie/broiler-turnaround-resetting-farm-healt… (2023).
6. Chaveerach, P., ter Huurne, A. A. H. M., Lipman, L. J. A. & van Knapen, F. Survival and Resuscitation of Ten Strains of Campylobacter jejuni and Campylobacter coli under Acid Conditions. Appl Environ Microbiol 69, 711–714 (2003).
7. Cook, K. L. & Bolster, C. H. Survival of Campylobacter jejuni and Escherichia coli in groundwater during prolonged starvation at low temperatures. J Appl Microbiol 103, 573–583 (2007).
8. Newell, D. G. & Fearnley, C. Sources of Campylobacter Colonization in Broiler Chickens. Appl Environ Microbiol 69, 4343–4351 (2003).
9. Battersby, T., Walsh, D., Whyte, P. & Bolton, D. Evaluating and improving terminal hygiene practices on broiler farms to prevent Campylobacter cross-contamination between flocks. Food Microbiol 64, 1–6 (2017).
10. Dzieciolowski, T., Boqvist, S., Rydén, J. & Hansson, I. Cleaning and disinfection of transport crates for poultry – comparison of four treatments at slaughter plant. Poult Sci 101, 101521 (2022).
11. Hald, B., Wedderkopp, A. & Madsen, M. Thermophilic Campylobacter spp. in Danish broiler production: A cross-sectional survey and a retrospective analysis of risk factors for occurrence in broiler flocks. Avian Pathology 29, 123–131 (2000).