Non beak-trimmed laying pullets kept with daylight may receive diets with only plant protein sources without increasing the risk for feather pecking and cannibalism

  • Christiane Keppler, Department of Farm Animal Behaviour and Husbandry, Faculty of Ecological Agricultural Sciences, University of Kassel, Germany
  • Ing agr Klaus Lange, Center of Animal Breeding (HDLGN), Neu-Ulrichstein, Germany
  • Dr Egbert Strobel, Thuekra, Thueringia animal feed mill, Gotha,, Germany
  • Prof Dr Ute Knierim, Department of Farm Animal Behaviour and Husbandry, Faculty of Ecological Agricultural Sciences, University of Kassel, Germany

    • Organic laying pullets should not be beak-trimmed, be reared with natural daylight and according to some guidelines receive no animal protein and synthetic amino acids. This may increase the risk for feather-pecking and cannibalism. This study aimed to examine possible effects of organic food rations (OF) with only plant protein sources versus conventional diets (CF) containing also animal protein sources on feather pecking, cannibalism and growth of non beak-trimmed pullets kept with daylight. Eleven strains were examined in two trials (A: 6 strains, B: 5 strains) in 22 groups of 85 with a stocking density of 7.4 birds/m². Each strain was treated as a paired sample receiving either OF or CF, with strains not being replicated. OF and CF had approximately the same total methionine and lysine contents. Food consumption was recorded weekly, plumage condition, injuries and body mass in week 16 of life (sample size A: 50, B: 40). Diet had no effect on percentages of pullets with featherless areas (A:CF 7.7±9.8%, OF 6.3±12.8%, p=0.859; B:CF 9.2±12.6%, OF 21.0±21.3%, p=0.160, paired t-tests) and injuries (A:CF 17.2±22.2%, OF 9.0±9.8%, p=0.0.516; B:CF 19.6±16.8%, OF 8.2±17.3%, p=0.899) which were blood-crusted and under the feathers in the tail area. The range in prevalences of featherless areas was high with 0% to 50%. Percentages of injured pullets correlated with feather damage (rSpearman A:0.753, p<0.01;B: 0.828, p<0.01). OF-birds tended to be lighter in trial A (A:CF 1617.0±138.4g, OF 1587.8±144.3g, p=0.059; B:CF; 1482.7±134.7g, OF 1501.6±148.7g, p=0.397), combined with a lower food consumption (p<0.001), but better food conversion rate (p=0.016). Mortality was low (A:CF 0.8±1.0%, OF 1.6±1.0%, p=0.328; B:CF 0.5±1.1%, OF 0.7±0.7%, p=0.621). Feeding of rations with only plant protein, but sufficient methionine and lysine contents may in certain cases negatively affect food intake, but does not necessarily pose an increased risk for feather pecking and cannibalism.