Injurious Pecking, commonly controlled by beak trimming (BT) is a widespread issue in laying hens associated with thwarted foraging. This controlled study compared the effect in intact and beak-trimmed pullets of providing pecking pans to 8 treatment flocks from 6 weeks of age. Flocks (mean size 6,843) comprised 8 British Blacktail, 6 Lohmann Brown and 2 Bovans Brown. All young birds (6-7 weeks) pecked more frequently at the pecking pans (mean 40.4) than older pullets (mean 26.0, 23.3 pecks/bird/minute at 10-11 weeks and 14-15 weeks respectively) (p<0.005).  There was no effect on feather pecking or plumage cover. Mean side-beak length and mean top-beak lengths were shorter in treatment flocks at 6-7 weeks and 10-11 weeks (p <0.001). Intact-beak treatment flocks had shorter mean side-beak length at 10-11 weeks (p < 0.001) and at 14-15 weeks (p<0.05) and mean top-beak length at 6-7 weeks (p < 0.05) and at 10-11 weeks (p < 0.05). BT treatment flocks had shorter side-beak and top-beak lengths at 6-7 weeks and at 10-11 weeks (p<0.001).  Beak lengths showed linear growth, with individual bird variation indicating a potential for genetic selection. The study demonstrated that abrasive material can reduce beak length in pullets.

Sixteen UK commercial rearing flocks were studied between September 2015 and December 2016. Half of the 16 flocks were infra-red beak trimmed (IRBT) at day old at the hatchery and the other half were intact-beak flocks (i.e. not trimmed) Strains were British Blacktail (n=8), Lohmann Brown (n=6) and Bovans Brown (n=2). Eight treatment flocks were randomly allocated and supplied with pecking pans containing an abrasive material, and 8 were paired control flocks reared on the same farm. Thus there were 4 intact treatment, 4 intact control, 4 trimmed treatment, and 4 trimmed control flocks.

At each visit (when birds were 6-7 weeks, 10-11 weeks and 14-15 weeks of age) 45 birds were randomly selected from different areas of the rearing house for beak measurement. Beak length was measured using Vernier callipers. Measurements of beak side-length and top-length were taken three times in succession to provide a mean length with an estimated accuracy of +/- 0.5mm. Top-length was measured from the frontal feather tract margin to beak tip. Side-length was measured on the right side, from nares to the tip of the beak. 

Individual birds were treated as independent datapoints in analysis. Analysis used the average of the 3 measurements. Data were not normally distributed and data were analysed using non-parametric tests.