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

A total of 2152 hens were fed one of two diets, with 25.0% wheat and 38.7% barley or 50.0% wheat and 13.7% barley. The hens were housed in battery cages with three hens per cage and in two aviary systems with tiered wire floors and litter-Lovsta with two tiers and Marielund with three tiers. Two hybrids were used: ISA Brown and Lohmann selected Leghorn. Production, interior and exterior egg quality, health, plumage, keel bone and foot condition were studied. The high-wheat diet resulted in inferior plumage condition owing to feather pecking, especially in the Leghorn hybrid, which in turn probably caused the higher feed consumption recorded. No other effects on production or egg quality traits were observed. Mortality, cannibalism, keel bone condition and foot condition were far more affected by housing system and hybrid than by diet. The highest mortality, mainly caused by cloacal cannibalism, was registered for ISA Brown in aviaries.