A computer model for welfare assessment of poultry production systems for laying hens

A computer model for welfare assessment in laying hens was constructed. This model, named FOWEL (fowl welfare), uses a description of the production system as input and produces a welfare score as output. To assess the welfare status a formalized procedure based on scientific knowledge is applied. In FOWEL the production system is described using 25 attributes (space per hen, beak trimming, free range, etc.), each with two or more levels, together defining the characteristics of a production system. A weighting factor is used for each attribute, based on the available scientific knowledge of the effects of the attribute levels on the welfare aspects. The welfare score of a production system results from the attribute levels combined with the weighting factors. The results show that feeding level, space per hen, perches, water availability and nests were the most important attributes. The attribute free range was of minor importance. FOWEL includes a description of 22 production systems. The welfare score of cage systems was low, of barn and aviary systems medium, and of organic systems high. The presence of a free range resulted only in a small improvement in the welfare score.