Modifications to broiler chicken housing to improve animal welfare
Conventional housing of broiler chickens raises concern for their welfare. High stocking densities and barren environments have the potential to contribute to lameness, skin lesions (i.e., hock burns, breast burns, footpad dermatitis*), heat stress, and increased fear that, in turn, can result in piling up and mortality.
Environmental enrichment can mitigate these welfare concerns by increasing activity levels and allowing for opportunities to perform species-specific behaviors which are important to ensure good welfare.
Studies investigating different types of enrichments have found a positive effect on broiler welfare due to a more varied behavioral repertoire and decreased laying time.
Some effective enrichments included in this newsletter are: elevated platforms, panels or barriers, straw bales, sand or roughage, and novel objects.
*Hock burns, breast burns and footpad dermatitis are brown/black skin lesions (necrosis) due to prolonged contact with litter.
Key characteristics of successful enrichments
- Increase species-specific (natural) behaviors
- Maintain or improve levels of health
- Improve economics of the production system
- Practical to employ
- Add environmental complexity
Even after years of strong genetic selection, domestic chickens are motivated to exhibit certain species-specific behaviors, including resting on elevated surfaces.
One way of fulfilling this need is to provide an elevated platform, often consisting of raised plastic slatted areas accessible by ramps. Broilers have shown a preference for raised platforms over perches, probably because platforms are easier to access and balance on compared to perches.
However, use of these structures largely depends on stocking density, design, accessibility, bird age, and their physical condition. It is important to keep in mind that birds are motivated to show perching behavior, but might not be able to do so.
Panels or barriers
Broilers commonly rest along the walls of the house, possibly to seek protection while sleeping. This can be an issue, as an uneven distribution of birds in the house can lead to reduced litter quality in those heavily-used areas (increased moisture and noxious chemicals), which can lead to contact dermatitis.
Additionally, when birds kept at high stocking densities gather to rest in a localized part of the house, you can expect an increase in disturbances of resting birds from those who attempt to move to another location.
Therefore, a more evenly distributed flock can be achieved by providing panels or barriers in the middle of the house.
Bales of substrate, such as straw or even bundles of wood shavings, can be used to stimulate activity and exploratory behavior in addition to providing a sense of protection while resting.
Sand or roughage
Two important natural (species-specific) behaviors of broiler chickens are foraging and dustbathing. Providing sand or other substrates (like peat, oat husks, or roughage) have been proven to increase time spent on these behaviors. It is possible to provide these substrates within a shallow wooden box or metal rings distributed evenly throughout the house.
Increasing the complexity of the environment reduces fear in poultry, thus improves animal welfare. This can be achieved by the provision of novel objects, such as colored plastic balls, plastic bottles, mirrors, hanging bundles of string, or other colorful items. The purpose of a novel object is to stimulate exploratory behavior and activity, and possibly inducing play behavior. Broilers will be less fearful towards humans when they have had access to a variety of novel objects.
In summary, providing environmental enrichment has many benefits for broiler health. In addition, these enrichments have the potential to increase species-specific behaviors, therefore improving welfare.
However, much is unknown about how stocking density impacts the positive effect of enrichment. Location and number of enrichments is an important factor to consider, as too few enrichments could result in crowding, competition over resources, or may only benefit a small number of birds.
While the mentioned enrichments are shown to have beneficial effects on broiler chicken welfare, it is important to note that research is ongoing to determine effects of specific enrichments on certain aspects of broiler health and productivity.
This article was originally published on Poultry Extension Collaborative (PEC) and it is reproduced here with permission from the authors.