Effects on production, health and egg quality of varying proportions of wheat and barley in diets for two hybrids of laying hens kept in different housing systems

abnormal behaviour affection podale alimentation des animaux animal feeding animal health aviaries battery cages calidad comportamiento anormal comportement alimentaire comportement anormal composition globale diet dieta eggs enfermedades de los pies feeding habits foot diseases gallina ponedora huevos layer chickens oeuf plucking plumage plumaje poule pondeuse proximate composition quality sanidad animal voliere