ASPETTI COMPORTAMENTALI, PRESTAZIONI PRODUTTIVE E QUALITÀ DELL'UOVO IN GALLINE ALLEVATE CON IL METODO BIOLOGICO

The aim of this trial was to study the effect of organic housing system on the behaviour, productive performance and the qualitative characteristics of eggs. The experiment was conduced directly in the field on Hy-Line laying hens from the beginning of the productive period (17 weeks of age) till the end of productive career. The animals were divided in two homogeneous groups and assigned to the following housing system: control, conventional cage (18 bird/m2) and organic 6 birds m2 in a covered straw-bedded house with access to a paddock (4 m2/bird). A standard feed with the same nutritive characteristics was given ad libitum to the chickens. For the organic, more than 80% of the ingredients (maize, wheat and whole soybean) were organically grown, as established by Regulation 1804/99. Ethological parameters (first impact, tonic immobility and behavioural patterns) and the plumage conditions showed better welfare conditions in organic laying hens. The greater movement of those animals lowered productive performances (lighter and less eggs); on the contrary the higher welfare and the minor overexploitation of organic animals permitted a longer productive life. The microbiological safety of eggs showed low levels of mesophila bacteria even though the organic system increased their mean value. There were few enterobacteria (< 100 CFU) and Salmonella spp. not present in any of the eggs analysed