Damage to birds may occur in various stages of the transport. Depopulation may cause broken and dislocated legs, especially if birds are carried on one leg. Not all housing systems are equally easy to depopulate. Although the overall incidence of leg fractures in DOA (dead-on-arrival) birds was low, Weeks et al (2012b) found in a small study of 24 loads that levels were 10 times greater for hens depopulated from colony (furnished) cages, than from free-range systems. Colony/furnished cases are now the only legal caged system within the EU. The depth of colony cages (from front opening to the rear) means it is hard to catch the hens at depopulation.
Pushing through narrow openings of crates often causes broken wings. More gentle and diligent work can reduce the number of breaks substantially. Systems with wider openings will also result in less broken bones.
In the crates birds may get bruises and scratches caused by other birds crawling over them. If crates are not closed properly, birds may get trapped, which may cause bruises, wounds or even death. Crates with damaged openings may lead to birds getting out too early, with the risk that they get stuck in the conveyer belt at the slaughter plant. Finally harsh handling during shackling may cause bruises, broken bones or wounds.
Due to all the stressors and possibly a suboptimal condition at the start of transport, not all birds reach the slaughter house alive. Global figures for dead on arrivals (DOAs) are unknown. Large surveys over several years in the Czech Republic and Italy revealed DOA percentages of resp. 1.01 and 1.22% (Voslarova et al., 2007; Petracci et al., 2006). Figures of 5 UK plants indicated a much lower percentage of DOAs: 0.27% (Weeks et al., 2012a). In 24 flocks monitored in The Netherlands during winter the DOA was on average 0.275% (Van Niekerk et al., 2014).
Further reading (by language)
- Petracci, M., Bianchi, M., Cavani. C., Gaspari, P. and Lavazza, A. (2006) Preslaughter mortality in broiler chickens, turkeys and spent hens under commercial slaughtering. Poultry Science,85, 1660-1664.
- Voslarova, E., Janackova, B., Rubesova, L., Kozak, A., Bedanova, I., Steinhauser, L. and Vecerek, V. (2007) Mortality rates in poultry species and categories during transport for slaughter. Acta Veterinaria Brno, 76, S101-S108.
- Weeks, C.A., Brown, S.N., Richards, G.J., Wilkins, L.J. and Knowles, T.G. (2012a) Levels of mortality in hens by end of lay on farm and in transit to slaughter in Great Britain. Veterinary Record, 170, 25 647. (online)
- Van Niekerk, T. G. C. M., H. Gunnink, and B. F. J. Reuvekamp. (2014). Welzijn van uitgelegde hennen tijdens vangen en vervoer in de winterperiode. Wageningen UR Livestock Research; Report 758.