Introduction
Organic egg farmers mainly rely on the same hybrids, breeding techniques and production schemes as conventional egg producers. This includes annual replacement of the laying hens. However, from an ethical point of view a longer life for laying hens is desired, not only because the hens can be used for a longer period but also less male chicks would have to be killed at one day of age. Birds have to moult their plumage from time to time. During this time they hardly take in any food and stop laying. This laying interval presents a recuperation period for the egg producing organs of the hen. After moulting, egg production is again higher and the egg quality is improved. In large flocks of laying hens moulting has to be induced to prevent social instability in the flock otherwise moulting could result in feather-pecking or even cannibalism.
Certain organic label organisations believe that the induction of a moult with food and light restriction might be too stressful for the hens. Therefore, the Swiss organic regulations forbid the induction of moulting. The following experiments were performed to provide information about the influence of moulting on the behaviour of hens
