TL;DR: In this article, the authors investigated the behavior of birds after partial beak amputation and found evidence for possible chronic pain in birds following the removal of the beak, and they interpreted these behavioural changes as instances of guarding behaviour and hyperalgesia.
TL;DR: If birds do have to be trimmed then the procedure should be carried out in young birds: from the birds' standpoint 1 d appears to be the most suitable.
Abstract: 1. To examine the effects of beak trimming on behaviour, beak anatomy, weight gain, food intake and feather condition 360 ISA Brown chicks were trimmed by hot cut or cold cut at 1 d or 10 d of age or were sham‐operated controls. The experiment was a 3 × 2 factorial design, with the chicks housed in littered pens in groups of 10 and observed for 6 weeks after trimming. 2. In the first week after trimming, when trimmed birds were compared with untrimmed controls, they were less active (sat and slept more), fed less, preened less and generally engaged in less beak‐related behaviour. 3. These differences waned sharply during week 2 and had disappeared by week 5. There were very few differences between hot‐ and cold‐cut birds. 4. There were also differences in production variables: trimmed birds grew more slowly during the week after trimming, their food intake was depressed for 3 weeks and food conversion efficiency improved for 2 weeks. 5. The only significant effect on feather scores was better plu...
TL;DR: Removal of half of the upper and less of the lower beak of pullet chicks at 4 weeks of age resulted in less pecking at feed, fewer non-agonistic pecks of all kinds, less moving and preening, and more inactive standing and crouching during the following 3 weeks.
TL;DR: Day-old debeaking had no significant effect on egg production traits other than a 5 day increase in sexual maturity, and in the groups debeaked at day-old, feed consumed in the period to 20 weeks of age was reduced by 475 grams per pullet and a 118 gram reduction in body weight persisted through 35 weeks ofAge.
TL;DR: Three-hundred-sixty, day-old Single Comb White Leghorn chicks were randomly placed in 8 treatment combinations and debeaking the birds either at 4 weeks or at 8 weeks of age reduced laying house mortality numerically and feed efficiency between the vaccinated and the nonvaccinated birds was not significantly different.