Causes of Mortality in Laying Hens in Different Housing Systems (2001-2004)
Author Information
Author(s): Oddvar Fossum, Désirée S Jansson, Pernille Engelsen Etterlin, Ivar Vågsholm
Primary Institution: National Veterinary Institute (SVA), Uppsala, Sweden
Hypothesis
This study aims to compare causes of mortality in different housing systems for commercial laying hens during the transition period in Sweden.
Conclusion
Laying hens in litter-based housing systems and free-range systems were found to be at higher risk of infectious diseases and cannibalism compared to those in cages.
Supporting Evidence
- More laying hens were submitted for necropsy from litter-based and free-range systems than expected compared to caged hens.
- Bacterial diseases were the most common causes of mortality in all housing systems.
- Colibacillosis was the predominant disease observed in laying hens.
- Cannibalism was a significant cause of mortality in litter-based and free-range systems.
Takeaway
This study looked at why laying hens died in different types of homes, finding that those with more space and outdoor access got sick more often than those in cages.
Methodology
The study analyzed necropsy results from 914 laying hens submitted for routine examinations at the National Veterinary Institute in Sweden between 2001 and 2004.
Potential Biases
There may be differences in the willingness of poultry farmers to submit birds for necropsy based on housing system.
Limitations
The study reflects a unique situation in Sweden during a specific transition period and may not generalize to other contexts.
Participant Demographics
Laying hens from various housing systems including cages, litter-based systems, and free-range systems, with flock sizes ranging from 400 to 37,000 birds.
Statistical Information
P-Value
p<0.001
Statistical Significance
p<0.001
Digital Object Identifier (DOI)
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