Effects of diet composition and beak trimming on the incidence of cannibalism in laying hens

A total of 2880 ISA Brown hens were used to investigate the effect of diet composition on the incidence of cannibalism in a 2 (dim and bright rearing) x 2 (with or without beak-trimming) x 4 (commercial diet, high-insoluble fibre diet, high-soluble fibre diet, high-soluble fibre diet plus enzyme) factorial experiment. Beak trimming had a profound effect (P<0.001) on cannibalism with mortality occurring predominantly in untrimmed birds. Total mortality for the trimmed birds was 0.14% and 0.77% for the pre-lay and early lay periods whereas it was 13.4% and 37.7% respectively for the untrimmed birds. Type of diet significantly affected cannibalism (P<0.01) with high-fibre diets appearing to be preventative against cannibalism. The highest mortality occurred in birds on the commercial diet, i.e. 13% and 29% for the pre-lay and early lay periods. Light intensity during rearing did not influence the incidence of cannibalism. The beak-trimmed birds had lower feed intakes than the non-trimmed birds (P<0.05). Diet also affected the feed intake (P<0.05), being lower (P<0.05) on the commercial diet than on the higher fibre diets. Egg production did not differ significantly between diets.