Effects of organic farming on egg quality and welfare of laying hens.

In the present paper are shown the results of a trial carried out during the first year of the project concerning the influence of housing system (outdoor vs battery cages) and feeding (conventional vs. organic diets) on some egg qualitative characteristics. During a four month-period, four groups of 27 Warren Isa Brown (8.5-9-month-old) laying hens were studied: AT ( in which hens were kept outdoor and fed a conventional diet); AB (in which hens were kept outdoor and fed an organic diet); GT (in which hens were kept into battery-cages and fed a conventional diet) and GB (in which hens were kept into battery-cages and fed an organic diet). The diets were formulated so as to supply the same amount of protein and energy. Freshly laid eggs were collected at the beginning of the trial and every three weeks up to the end of the trial to determine some physical and qualitative parameters. Feed intake and egg production of groups AT and GT were, on the whole, higher than those of group AB+GB. All the eggs were classified into the category L, with a weight comprised between 63.00 and 72.99 g (Regulation EC No. 2295/2003, modified by Regulation EC No. 1515/2004). The experimental conditions did not effect the bird’s health and mortality rate was very low. No behaviorale anomalies were observed. At the end of the trial, the heavier eggs were observed in groups fed the conventional diet, while the higher percentage of eggshell was detected in eggs of group AT+AB. The natural daylight and motor activity of outdoor animals were supposed to increase mineral metabolism leading to a better mineral deposition into eggshell. Haugh index and pH values were improved in eggs deriving from hens allocated in cages. Yolk from groups AT and AB was heavier and more intensively coloured, owing to the possibility to eat feeds containing xanthophylls, such as grass, herbs and insects. The comparison between the type of diets (conventional vs organic) did not pointed out any significant difference. Based on these results, we can conclude that some egg quality characteristics can be significantly influenced by the housing system and only at a slightly extent by the diet