Relationship between maximum daily temperature and mortality of broiler chickens during transport and lairage

Abstract

1. Based on records of all (n = 59 171 843) broiler chickens slaughtered over three years at one processing plant, the overall mortality of birds in transit was 0·126%.

2. There was a pronounced seasonal effect with increased mortality in the summer months, particularly June, July and August. Mortality increased when the maximum daily temperature (measured in the shade) rose above about 17°C at the start of the summer.

3. Between 17·0 and 19·9°C, mortality was 30% higher than at lower temperatures. Between 20·0 and 22·9°C it increased 2·6-fold, and at temperatures of above 23°C 6·6-fold. There was no evidence of birds dying from hypothermia at very low ambient temperatures (down to −1°C).

4. The implication from the results is that above a maximum daily temperature of 17°C steps may need to be taken to ameliorate the damaging effects of transport on bird welfare.

Acknowledgements

We would like to thank the management of Lloyd Maunder Agriculture Ltd (Willand, Devon), especially Mr David Lanning, for allowing us access to their records of mortality, and the Meteorological Office for access to the temperature data.