Antibiotic reduction journey – A case study


Avara Foods processes 4 million birds per week, making it one of the largest food companies in the UK. It is vertically integrated with 30 rearing farms, 60 laying farms, 6 hatcheries, 150 broiler farms, 3 feed mills and 1 laboratory all contributing to the production of safe, affordable poultry meat.

Antibiotic reduction meets a problem

Avara Foods has been on its antibiotic reduction journey for many years, and completely removed antibiotic growth promoters from all diets in 2000. However, in 2019, the company noticed an increase in bacterial infections. The cause was identified as Enterococcus caecorum. Antibiotics were prescribed by the veterinarian team where the problem occurred. However, the company’s aim overall was to reduce antibiotic usage and an action plan was needed in order to support this aim.

Action plan implementation

The first action plan iteration focused on improving hygiene throughout the supply chain. Water hygiene had always been a priority, but a full physical clean, disinfection and sanitation was conducted. Support was provided by suppliers to ensure the correct standards were achieved during the clean-up. The prophylactic use of antibiotics was allowed for one crop cycle as a firebreak, to try to reduce the bacterial load prior to the deep clean. Serving as a temporary measure that would support a longer-term reduction in use.

The hygiene focus for water, breeders, hatcheries, and broilers resulted in an initial drop in bacterial infections; however, these levels tended to increase over time. Therefore, it was decided that a second action plan was required.

Revised action plan implementation

Avara Foods was now very aware of the impact the bacteria was having on its production and so a more detailed approach to reducing bacterial load was taken. This time the action plan consisted of:

  • two cycles of prophylactic antibiotic use in day old chicks
  • more stringent rules around hatching egg selection and hygiene
  • further improvements to farm hygiene
  • improvement of chick starter practices
  • introduction of Sonas technology in hatcheries
  • introduction of a multi species probiotic

More stringent hatching egg selection

One of the biggest changes was the rejection of all B Grade eggs before setting. At the time, 95% of Avara’s eggs were classed as A Grade, and 5% were B Grade. Disposing of all the B Grade eggs meant that up to 200,000 hatching eggs were lost each week. When coupled with the compensation paid to flock farmers for the chick income they didn’t receive, this was a costly but effective strategy.

Double deep clean

Each farm had two turnarounds for deep cleaning following the two prophylactic antibiotic crop cycles. Support was again given to growers to ensure facilities were properly cleaned and allowed to dry before the introduction of the next flock.

Implementing new hatchery technology

To eliminate fluctuations in sanitation application, the Sonas technology was introduced. Sonas controls the levels of formaldehyde in the hatchery machines, delivering a precise, low concentration which ensures effective bacterial inhibition as well as staff safety. Following the implementation of Sonas (Figure 1), significant improvements were seen in:

  • 7-day and final mortality,
  • rejects, and
  • growth performance.
Figure 1. Formaldehyde levels in hatchery machines over time using traditional Formalin application (purple line) and Sonas technology (green line) | (Source: Avara, 2023)

Brooding temperature adjustment

Following a UK government scheme to promote renewable energy, many poultry growers switched to biomass heating for their sheds. Due to this incentivised heat source, temperatures tended to increase during the growing phase. Investigations, particularly on farms with recurring problems, highlighted that in some cases, chicks were being brooded at temperatures that were higher than recommended. Heat stress can lead to ‘loose junctions’ in the gut, allowing easier access for bacteria to enter the bloodstream. Lowering the brooding temperature to 31-33oC reduced this stress.

Probiotics as an additional measure

The final piece in the puzzle was about maintaining good leg health. Previous experience highlighted that prophylactic antibiotic use, while effective in the short term, showed diminishing returns over longer periods. In search of a more sustainable solution, we partnered with nutrition experts and conducted a literature review. Probiotics emerged as a promising approach.

One particular study investigated the potential of PoultryStar®, a probiotic feed additive, to establish a healthy gut microbiome in chicks. The original research focused on reducing lameness, but we hypothesized that the same mechanism – competitive exclusion – could also help minimize bacterial infections and leg culls.


Avara Foods found that:

  • Egg and hatchery hygiene is key
  • Cleaning and disinfection of farms is vitally important – there needs to be enough downtime for this step to happen thoroughly and for the sheds to dry out before new birds are introduced
  • Water quality remains important and there is always room for improvement in this area
  • Brooding temperatures should be controlled so the chicks are not thermally challenged in the first day
  • Supplementation with PoultryStar® helped reduce leg culls

But above all, reducing the bacterial load in the supply chain is the most important priority in reducing antibiotic use. Other interventions can be called upon to provide short-term relief from bacterial problems, but long-term, sustainable results can only be achieved when efforts to improve hygiene standards across the supply chain are properly implemented.

Published on

10 June 2024


  • Poultry
  • Antimicrobial Resistance
  • Pre-Probiotics

About the Author

Stephen Dart - General Manager of Avara Foods

Stephen Dart is the General Manager for the chicken breeder and broiler operations at Avara Foods in the UK. He is responsible for the daily operations of these agricultural divisions with the key focus being on – bird welfare, sustainability, compliance, efficiency, and cost. In addition, Stephen is responsible for the strategic development of the required agricultural asset base, working closely with their farming partners to expand and reinvest in facilities to meet the changing business needs. In the last 15 years, Stephen has also had representation at a UK industry level by chairing and having representation on several British Poultry Council committees working with government departments on several subjects involving – the environment, welfare, antibiotics, and legislation.


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