On organic and free-range poultry farms, free-range is provided for animal welfare reasons. However, organic/free-range farmers report sightings of birds of prey and foxes attacking their chickens and, as they are regularly finding chicken carcasses in the free-range, they attribute the death of those chickens to predators. In addition, and in contrast to indoor poultry farmers, they report hundreds of missing chickens at the end of the production period. They assume these chickens have left the free-range at the hands of predators. This study investigated whether birds of prey kill chickens on organic/free-range egg production farms, and their impact, in terms of numbers of chickens and yield losses. Field observations were done on 11 organic/free-range farms and, in an online survey, organic/free-range farmers were asked about their farm records. During 79 observations at those 11 farms, a bird of prey was seen 141 times, including 16 attacks by common buzzards and northern goshawks. Based on the results from the online survey (n = 27 farms experiencing predation), on average, 3.7% of the hens in organic/free-range flocks were estimated to have been killed by predators. After calculating missed yield per killed hen, it was roughly estimated that, per flock, predation caused yield losses of EUR 5700 on an average organic farm (size 12,700 hens), and EUR 6700 on an average free-range farm (size 25,000 hens).
Pagina's / pages: 17
Type: Wetenschappelijk artikel
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Abstract / summary in English:
Keywords in English: predation; mortality; free-range laying hens; organic laying hens