M. A. Grashorn

Effects of pasture management on poultry welfare and meat quality in organic poultry production systems

Outdoor access is a defining characteristic of organic poultry that provides poultry with fresh grass, insects and worms that may lead to enhanced product quality. There is evidence that meat from pastured-based poultry may contain some additional nutritional benefits through lower fat content, as well as higher vitamin and mineral contents. At the same time, under good pasture management, bird health and welfare can be achieved. This review gives an overview on the pasture management practices that can be employed to prevent potential risks in organic poultry systems such as uncontrolled weather conditions or mortality due to predators. This paper discusses the various effects of pasture management on (a) poultry health and welfare, including physical comfort, absence of hunger and disease, possibilities to perform motivated behaviours and (b) meat quality, including both consumer and nutritional quality and sensory attributes as related to pasture synthesis and intake.

Quantitative Genetic Analysis of Traits Related to Fear and Feather Pecking in Laying Hens

Feather pecking is a well known problem in flocks of laying hens. It is partially controlled by genetics. Fear is frequently reported to be related with feather pecking. The present study reports the result from a quantitative genetic analysis of feather pecking and three fear test traits in laying hens. Fear was recorded by the tonic immobility test, the open field activity and the emergence box test. These were recorded at a juvenile and adult age of the hens. The heritability of feather pecking was 0.16, and in the range between 0.07 and 0.14 for the fear test traits. Genetic correlations between fear measured in the juvenile and in the adult age point to different but correlated traits. Tonic immobility measured early in life was moderately correlated with feather pecking and might be used as a breeding criterion to reduce feather pecking.

Research into poultry meat quality.

1. Research in the field of poultry meat quality has become more varied during the last 50 years. Besides meat content and microbial condition, animal welfare issues during the slaughter process, muscle morphology, physiology of meat ripening, impact of slaughter process on meat quality, sensory attributes of meat and meat processing have come into focus. 2. The present review summarizes findings and developments in the fields of muscle physiology, meat ripening and meat quality aberrations (like PSE), nutrient composition and sensory qualities, effect of the slaughter process on carcass and meat quality, hygienic conditions and product safety during slaughtering, all based on selected papers published in British Poultry Science during the last 50 years. 3. Some special findings and conclusions are lifted out of the whole results presented in the papers to indicate their importance and to show their contribution to the development of knowledge in the respective field.

The presence of extreme feather peckers in groups of laying hens

Feather pecking is a serious economic and welfare problem in laying hens. Feather damage occurs mainly through severe feather pecking (SFP). Selection experiments have proved that this behavior is heritable and lines have been divergently selected for high (HFP) and low feather pecking (LFP). The number of bouts of SFP per hen follows a Poisson distribution with a maximum nearby 0. A few studies indicate that the distribution within flocks is not homogenous but contains sub-groups of birds showing extremely high levels of feather pecking (EFP). It was the aim of the current study to re-analyze data on SFP of lines selected for HFP/LFP and their F2 cross so as to uncover hidden sub-populations of EFP birds. Data of seven selection generations of HFP and LFP selection lines as well as their F2 cross have been used. We fitted a two-component mixture of Poisson distributions in order to separate the sub-group of EFP from the remaining birds. HFP and LFP lines differed mainly in mean bouts per bird. The proportion of EFP was only marginal in the LFP as compared with the HFP and the F2 population. Selection for LFP did not result in total elimination of EFP. The presence of even small proportions of EFP may play an important role in initiating outbreaks of feather pecking in large flocks. Further studies on feather pecking should pay special attention to the occurrence of EFP sub-groups.