Review of rearing-related factors affecting the welfare of laying hens

Abstract

Laying hens may face a number of welfare problems including: acute and chronic pain caused by beak trimming; exaggerated fearfulness that may cause stress and suffocation; difficulties in locating resources, resulting potentially in emaciation and dehydration; frustration and boredom, caused by an environment that is barren; feather pecking; cannibalism; foot lesions; and bone fractures. In Europe, a greater proportion of laying hens are housed in non-cage systems compared to the rest of the world. The extent of the different welfare problems may therefore vary between countries as the type of housing system influences the risk of suffering. More generally, many of these welfare problems are influenced by the rearing environment of the pullets. This article therefore focuses on welfare problems in laying hens that can be traced back to rearing. Factors that have been studied in relation to their effects on bird welfare include beak trimming, housing type, furnishing, enrichment, feeding, stocking density, flock size, sound and light levels, concentration of gasses, age at transfer from rearing to production facilities, similarity between rearing and production facilities, competence of staff, and interactions between bird strain and environment. The present review aims to summarize rearing-related risk factors of poor welfare in adult laying hens housed according to European Union legislation. It aims to identify gaps in current knowledge, and suggests strategies for improving bird welfare by improving rearing conditions. Two main conclusions of this work are that attempts should be made to use appropriate genetic material and that beak trimming should be limited where possible. In addition to this, the rearing system should provide constant access to appropriate substrates, perches, and mashed feed, and should be as similar as possible to the housing system used for the adult birds. Finally, young birds (pullets) should be moved to the production facilities before 16 weeks of age. The measures outlined in this review may be useful for improving the welfare of pullets and adult laying hens.

Presence of roosters in an alternative egg production system aiming at animal welfare

“…Rocha et al (2008) stated that environmental enrichment is an important tool to minimize cannibalism. Janczak and Riber (2015) also pointed out that, as a result of a continuous genetic selection, it is possible that the current genotypes reared for egg production are less susceptible to feather-plucking and cannibalism, emphasizing that new studies are necessary to investigate the need to practice debeaking.…”

Índice produtivo e qualidade de ovos de galinhas poedeiras submetidas a diferentes métodos de debicagem

“…É possível constatar que a não realização da segunda debicagem exerce poucos efeitos negativos sobre o desempenho produtivo de poedeiras comerciais, pois não se observou frequência de canibalismo entre as aves e apenas a massa corporal e o comprimento de bico foram alterados pela aplicação da debicagem à décima semana de vida. Observa-se que as linhagens modernas estão menos suscetíveis ao canibalismo e à bicagem de penas (Janczak & Riber, 2015) e são consideradas mais dóceis e adaptadas ao sistema de produção em gaiolas.…”

Relationships between range access as monitored by radio frequency identification technology, fearfulness, and plumage damage in free-range laying hens

“…In addition to fearfulness, range use seems to be dependent on a number of other variables. These may include birds' previous experience with the environment and the outdoor range (Grigor et al, 1995;Janczak and Riber, 2015), pop-hole size, accessibility to the range (Gilani et al, 2014), and structures on the range (Hegelund et al, 2005;Rault et al, 2013). In the present experiment, the range areas were fenced off and had wire mesh across the top; hence the birds were protected from predators.…”