Provning och utvärdering av nya typer av artificiellt ljus i hönsstallar

The lighting environment in egg production is crucial for laying hens and their egg laying. Compared to humans, birds have a fourth type of cone in the retina which allows the perception of electromagnetic radiation below 400 nm. Birds also have a greater spectral sensitivity than humans and a high critical flicker frequency, 100 Hz, therefore they may react differently on the lighting environment than humans. According to the Swedish animal welfare law all farm animals should be housed in houses with daylight inlets. However, there are no guidelines for how these daylight inlets should be designed or placed in the hen house. Inappropriate lighting management or daylight inlets may increase the risk for behavioural problems, e.g. cannibalism and feather pecking. Incandescent light has until recently been the most common type of artificial light in Swedish hen houses. Due to the EU ban of incandescent light bulbs there is, however, a need for replacement lighting. There is also need for alternative light sources in existing layer houses, with unsuitable daylight inlets, as well as guidelines for how to design day light inlets, when building new hen houses. The aim of this project was to evaluate an alternative light source unsuitable daylight inlets and an alternative light source to incandescent light. Furthermore, guidelines on how to design and place daylight inlets were put together, based upon a literature study and a field study of existing daylight inlets in Sweden. A new lighting equipment (HATO® Agricultural Lighting) has been introduced in Sweden. It is reported to have a spectral range more similar to natural light with a more even wavelength distribution between 400 and 700 nm, and a higher content of the ultraviolet A light (UVA). In order to be approved as an alternative to daylight inlet the lamp must not cause decreased bird welfare. A field study of two farms with laying hens in aviary and furnished cage and one rearing farm (aviary), already equipped with HATO®, were therefore performed during one production period. LED (Light Emitting Diode) was evaluated as an alternative light source to incandescent light. A field study of one layer farm during one production period was performed. The lighting environment in the farms was recorded regarding distribution intensity and spectral distribution in the aisles, at the feeding troughs and at the nests. Clinical inspections and qualitative behavioural studies were performed on a random sample of 100 birds at each farm. Pullets were inspected at 1, 10 and 14 weeks of age, and the production flocks were inspected at 35, 55 and 70 weeks of age. The light intensity in the stables with HATO® was 12-70 lux at the rearing farm, 2.5 - 26 lux in the house with furnished cages and 7.6 - 26 lux in the aviary. In the farm with LED the light intensity was 0.7-11 lux. Production of the batches was normal compared to national standards. In the flocks studied the frequencies of negative behaviour such as tense or nervous were low. Body condition was normal and occurrence of comb damage was low. Feather pecking was observed but a clear connection to the housing or light system cannot be made. Feather pecking is also reported in hens with access to outdoor areas. When using daylight inlets, it is important that the light is evenly distributed in the stable and that the daylight is coordinated with the existing lighting program in the stable.