Feather Pecking in Non-Beak-Trimmed and Beak-Trimmed Laying Hens on Commercial Farms with Aviaries

Abstract

Severe feather pecking (SFP) is a major animal welfare problem in layers. It results in pain and injuries in the affected animal. It was the aim of this study to gain insight into the actual pecking behavior of laying hens kept on commercial farms with flock sizes common in practice. We observed aggressive pecking and SFP in non-beak-trimmed and beak-trimmed flocks of laying hens and investigated possible influencing factors. The study took place on eight conventional farms in Germany with aviaries, including three farms with a free range and a winter garden, one with a free range and one with a winter garden. Pecking behavior was observed during three observational periods (OPs): OP 1, at the peak of the laying period between the 28th and 33rd week of life; OP 2, in the middle of the laying period between the 42nd and 48th week of life; and OP 3, at the end of the laying period between the 63rd and 68th week of life in one laying period. Videos were analyzed using behavior sampling and continuous recording. We found that SFP occurred in all flocks, but the pecking rate differed significantly between the flocks. SFP correlated positively with the number of hens per square meter of usable area, with statistical significance in the litter area (r = 0.564; p = 0.045). The multivariate analysis revealed that access to a winter garden or free range significantly reduced the SFP rate on perches (p = 0.001). The stocking density (number of birds per usable square meter) had a significant influence on the SPF rate in the nest-box area (p = 0.001). The hybrid line had a significant effect on the SFP rate on perches and in the nest-box area (p = 0.001 each). Lohmann Brown hens in mixed flocks had a higher SFP rate (significant in OP 2) than those in homogeneous flocks, indicating that mixed flocks may be a risk factor for SFP. Lohmann Brown hens pecked significantly less than Dekalb White hens in the litter area (p = 0.010) and in the nest-box area (p = 0.025) and less than Lohmann Selected Leghorn hens in the litter area (p = 0.010). Lohmann Brown and Lohmann Selected Leghorn hens showed increasing SFP rates during the laying period. All hybrid lines had significantly higher SFP rates in the litter area, followed by the nest-box area and perches. These findings emphasize the importance of providing enough litter, litter areas and environmental enrichment. We found a significant positive correlation between aggressive pecking and SFP—in OP 1: rho (Spearman) = 0.580, p < 0.001; OP 2: rho = 0.486, p = 0.002; and OP 3: rho = 0.482, p = 0.002 (n = 39) —indicating that SFP may lead to a higher stress level in the flock. Beak trimming reduced pecking rates but did not entirely prevent SFP. Instead of subjecting chicks to this potentially painful procedure, reasons for SFP should be addressed. In conclusion, our data suggest a positive influence of a lower stocking density and the provision of a winter garden or free range for additional space. The hybrid line had a significant influence on the feather-pecking rate on perches and the nest-box area. Aggressive pecking and severe feather pecking correlated positively. We assume that vigorous and painful AP were an additional stress factor, especially in non-beak-trimmed flocks, leading to more SFP in due course. Beak trimming had a reducing effect on SFP. However, our results showed that non-beak-trimmed flocks could be kept without major outbreaks of SFP.

Individual plumage and integument scoring of laying hens on commercial farms: correlation with severe feather pecking and prognosis by visual scoring on flock level

“…During the laying period, the behavior of the animals was recorded in 3 observation periods ( OP ): OP 1 at the peak of the laying period between the 28th and 33rd wk of life, OP 2 in the middle of the laying period between the 42nd and 48th wk of life, and OP 3 at the end of the laying period between the 63rd and 68th wk of life ( Table 1 ). Additional information on the flocks is published in Schwarzer et al (2021) .…”

“…As it was not possible to view all animals in the videos, we calculated the mean number of pecks per bird by dividing the total number of pecks observed in each observation period by the number of animals in the flock (severe feather pecking/bird, SFP/B ). The results of the pecking behavior are published in Schwarzer et al (2021) .…”

Effects of Stocking Rate and Environmental Enrichment on the Ontogeny of Pecking Behavior of Laying Hen Pullets Confined in Aviary Compartments during the First 4 Weeks of Life

“…This effect was significant for all EGs; however, it was most pronounced for NE. Other studies found the highest pecking rates in the litter area, as compared to perches and the nest box area in commercial laying hen flocks but did not observe aviary platforms [ 24 , 41 , 42 ]. The study of Elger, however, found a significant effect of the functional area “aviary platforms” on SFP in laying hens housed in commercial aviaries, compared to the functional areas “litter area” and “perches” [ 43 ].…”

“…Regarding the location of feather pecking in the housing system, the studies of Johnsen et al, and of Hansen, observed most feather pecking bouts on the perches, followed by the litter area and feeding platforms [ 22 , 31 ]. Other authors reported feather pecking predominantly in the litter area [ 24 , 41 , 42 ] or on the aviary platforms [ 43 ]. A layer of chick paper with food placed on top is usually put on the aviary slats before placing the pullets as part of the coccidiosis vaccination and feed-management strategy [ 20 ].…”

Influence of Increased Freedom of Movement on Welfare and Egg Laying Pattern of Hens Kept in Aviaries

“…The back, breast and neck regions are largely acknowledged in the literature as the areas in which feather pecking lesions are observed more frequently [ 31 , 32 , 34 , 35 , 36 ]. This increase in feather pecking behaviour in VM and reduction in FM compared to the control group, however, highlights an inconsistent effect of ramps on animal welfare, seeming to indicate that pecking is more present when vertical movement is allowed but lateral movement is limited (VM group), therefore in this group the (relatively) higher density and competition, although only in localized areas delimitated by partitions and likely at the higher end of the ramps, may have triggered feather pecking behaviour [ 37 , 38 ].…”