Dietary prevention of cannibalism in layers

Severe beak trimming results in chronic pain in laying hens (Lunam and Glatz, 1995). Consequently, some European countries have imposed either a total ban or reduced the severity of beak-trimming. This has led to major outbreaks of cannibalism in birds housed in production systems, such as barn and free range, and welfare-friendly methods of controlling cannibalism, e.g., dietary management and low-light housing, are urgently required. We reported (Hartini et al., 2001) that cannibalism mortality in untrimmed birds fed a commercial diet was 28.9%, but was 14.3%, 15.9% and 17.8%, respectively, in birds fed diets containing higher levels of fibre. To investigate the mechanisms whereby high fibre diets prevent cannibalism, we used the same four diets (Diet 1: commercial; Diet 2: Millrun; Diet 3: Barley, and Diet 4: Barley + enzyme) used by Hartini et al. (2001) and determined digesta viscosity and transit time in ISA Brown hens at 42 weeks of lay. Eight birds per diet were kept in individual cages and fed the experimental diets for 7d. On d8, all birds were fasted for 2h and given 10g of their diet containing a digestibility marker (400mg/kg alkane C₃₈H₇₄). After two hours, excreta were collected every 30 min for 8h, alkane concentrations were determined and digesta transit time calculated... The birds were fed their respective diets for a further 7d and were killed and viscosity measures made on their gut contents. The ileal viscosity values (mPa.s) for diets 1, 2, 3, and 4, were 8.4, 5.6, 4.8 and 3.5 respectively, and were significantly (P<0.01) different from one another.