Review of environmental enrichment for broiler chickens

Abstract

Welfare problems are commonly found in both conventional and organic production of broiler chickens. In order to reduce the extent of welfare problems, it has been suggested to provide stimulating, enriched environments. The aim of the present paper is to provide a review of the effect on behavior and welfare of the different kinds of environmental enrichments in the production of broilers that have been described in the scientific literature. Environmental enrichment is defined as an improvement of the environment of captive animals, which increases the behavioral opportunities of the animal and leads to improvements of the biological function. This definition has been broadened to include practical and economic aspects, as any enrichment strategy that adversely affects the health of animals or that has too many economic or practical constraints will never be implemented on commercial farms and thus never benefit animals. Environmental enrichment for broilers often has the purpose of satisfying behavioral needs and/or stimulating the broilers to an increased level of activity, which among others will reduce the occurrence of leg problems. Potentially successful environmental enrichments for broiler chickens are elevated resting-places, panels, barriers, and bales of straw ("point-source enrichment"), as well as covered verandas and outdoor ranges ("complex enriched environments"). Many of the ideas for environmental enrichment for broilers need to be further developed and studied, preferably in commercial trials, with respect to the use, the effect on behavior and on other welfare aspects such as leg health, and the interaction with genotype, production system, stocking density, light, and flock size. In addition, information on the practical application and the economics of the production system is often lacking, although it is important for application in practice.

Literature update on effective environmental enrichment and light provision in broiler chickens

“…Effective environmental enrichment stimulates natural behaviour, can reduce negative feelings such as anxiety, and contributes to experiencing positive emotions (Riber, et al, 2018) and thus potentially contributes to broiler chickens' welfare. Although much research is currently being done on effective environmental enrichment for broiler chickens, the majority of previous and current research focused on regular, fast-growing breeds (Bailie, et al, 2013;Bailie, et al, 2018a;Bailie, et al, 2018b;Bailie and O'Connell, 2014;Baxter, et al, 2018b;De Jong and Gunnink, 2019;Riber, et al, 2018). A one-to-one translation of effects of environmental enrichment on behaviour and other welfare indicators of fast-growing broiler chickens into slow-growing breeds is not possible, because the behavioural needs of slow-growing breeds may differ, and they are usually much more active and have a different time budget than fast-growing broiler chickens (Bokkers and Koene, 2003;Rothschild, et al, 2019).…”

“…In the current report, we aim to summarise the state-of-the art of knowledge with respect to effective environmental enrichment and lighting conditions for broiler chickens, as a starting point to define research questions specifically targeted to optimise housing conditions for slow-growing broiler chickens. With respect to environmental enrichment, the publication of Riber and collaborators (Riber, et al, 2018) has been used as a starting point and more recent information has been collected and summarised. With respect to lighting, in consultation with stakeholders we chose to limit the literature study to three potential interesting areas of research: (1) effects of natural light provision and its variation across the broiler house; (2) effects of ultraviolet wavelengths (UV) on chicken behaviour; and (3) light colour preferences of broiler chickens.…”

“…The present literature study is based on the review paper from Riber and collaborators (Riber, et al, 2018), which gives an overview of the different kinds of environmental enrichment in all types of production systems for broiler chickens. The review was based on relevant scientific literature from the database "Web of Science" retrieved using the key words "broiler environmental enrichment."…”

“…Op weg naar integraal duurzaam dierenwelzijn (2019) -which is to gain insight into the needs of slowgrowing chickens with regard to environmental enrichment and light provision -the summary tables included in the paper of Riber and collaborators (Riber, et al, 2018) were expanded with relevant scientific literature published in or after the year 2017, up until year 2019. Most references were retrieved from the database "Web of Science" on June 3-5, 2019, using the same key words as in the paper of Riber and collaborators (Riber, et al, 2018). Moreover, two extra scientific reports have been included: one pilot-study report from Wageningen Livestock Research (De Jong and Van Wijhe-Kiezebrink, 2014) and a recently finished Master thesis report from Wageningen University and…”

“…In addition, a practical inventory was carried out with the help of stakeholders (Janny Hermans from The following types of point-source objects used in conventional environments are reviewed in this section: perches and platforms; panels, barriers and bales of substrates; materials and methods stimulating foraging and dustbathing behaviour; and novel objects. Table 1 presents the main features of the perches and platforms used in the studies reviewed by Riber and collaborators (Riber, et al, 2018), updated with results from recent publications.…”