The type of housing and stocking densities of egg laying hens has become a growing concern for the egg laying industry and a point of interest for animal welfare conscious consumers. The typical conventional battery caged hen in Alberta receives 432 square centimetres floor area. New requirements in the European Union (EU) will require all hens by 2012 to be provided with enriched cages and receive 750 square centimetres of floor area per bird. The EU decision was driven by the recognition that the performance of natural behaviours is important for hen welfare. Enriched cages are furnished with nest boxes, scratch pads and perches.
“There are many variables to consider when designing and stocking enriched cages,” says Adrienne Herron, livestock welfare technical transfer specialist, with Alberta Agriculture and Rural Development, Edmonton. “To answer some of the welfare and housing questions a research study was conducted at the Lacombe Research Station by Dr. Nigel Cook. The principle objective of this research was to assess the benefits of converting a commercially available system from battery cages to furnished colony cages. The research used several measures to determine hen welfare: direct behavioural pattern observations, fecal and blood biomarkers, and thermal heat imaging to determine feather wear patterns.”
“In this study, hens exhibited very strong preferences to roost on perches and the provision of perches improved hen welfare,” says Cook. “Hens also showed a preference for using the nest box by the number of eggs laid within the nest box and for using the scratch pads by the reduced length of the nail on the middle toe. The strong preferences for hens to use the furnishings in this study suggest that conventional cages do not allow for sufficient expression of natural behaviours.”
There was no significant difference in the levels of stress hormones seen in the blood and fecal materials from either housing group. It is possible, however, that these measures may not be sensitive enough to detect the differences in housing conditions. It is also possible that the space allocated to each bird in the conventional cages in this study may have affected the results as birds received nearly double the floor space of a commercial bird.
The use of heat imaging or IRT appears to have many scientific and practical applications. The thermal imaging used in this study was able to detect the heat losses due to feather loss and determine if the feather loss was due to feather pecking or wear. Feather losses seen in this study were accounted to wear on furnishings rather than feather pecking.
“Important notes from this study included the demonstration that commercial conventional cages could be easily converted into furnished colony cage systems,” says Herron. “The ideal colony size is probably between 10 and 20 birds, and 20cm of perch access per bird was an excellent compromise between loss of insulation and the hens’ urge to perch. The cost of feather wear or heat loss in terms of greater feed consumption is an area that requires further study.”
Financial support for this research was provided by a grant from the Alberta Livestock Industry Development Fund (ALIDF) with contributions from Alberta Egg Producers and Alberta Farm Animal Care (AFAC).