Economic consequences of stopping “thinning” in broiler production

Flock “thinning” is often used in broiler production to optimize the use of farm space and raise more birds while complying with EU regulations that set the maximum stocking density in a building at 42 kg/square meter.

During a partial depopulation, the maximum density allowed by law is reached more quickly and part of the herd is sent for slaughter earlier while the remaining animals continue until the end of the production cycle.

Biosecurity risk

But this practice constitutes a serious break in the biosecurity of the farm which can lead to the introduction of various pathogens into the herd, including Campylobacter spp. The partial cull is stressful for the broilers who are deprived of food and water several hours before the arrival of the catching team.

The capture team can introduce Campylobacter into the herd, as the bacteria has been found on boots, clothing, and other equipment prior to being used in a partial depopulation. Research has revealed that broiler transport crates are often contaminated with Campylobacter.

Consequences of thinning on production

Researchers from the University of Ghent, Belgium, investigated whether flock depopulation could increase the risk of Campylobacter spp being introduced into the poultry house. In Belgium, in conventional production, about a quarter of the herd is slaughtered at 35 days and the rest slaughtered at 42 days. A simulation was carried out to assess the consequences of “thinning” on production.

In the study, the production of a building performing a partial depopulation of 25% of the herd at 35 days of age before final slaughter at 42 days was compared to a production system where partial depopulation was not carried out. Differences in production costs, profits and technical performance parameters were assessed.


The model indicated that stopping partial depopulation reduces production by between 16 and 24%, which translates to a 14% reduction in profit per kg live weight and a 31% reduction in profit per production cycle.

To compensate for the shortfall, the price of meat would have to be increased by 3% from a starting price of 87.44 euro cents.

The researchers said that for current conventional broiler production, it may be financially difficult to stop partial depopulation practices. Instead, focusing on external biosecurity to prevent the introduction of Campylobacter into poultry houses may be the right compromise.

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