Nina Volkmann

Background: Feather pecking and cannibalism are multifactorial problems that affect most laying hens in modern husbandry. As to which hens are predisposed to being pecked and suffer from feather and skin damage is still under investigation. Animals, Materials and Methods: In this retrospective study, hens’ live weight and plumage condition were each recorded and investigated for a potential relationship. Data were collected from 5,764 laying hens (various genetics) from 17 flocks (alternative housing systems) during several visits over their entire laying period. At each visit, a sample of hens was weighed and scored for plumage und skin damage. Afterwards, depending on each hen’s weight deviation from the target weights provided by the breeders (WTW), they were grouped as too light with < -10% of target weight (L-hens), as good showing ± 10% of target weight (G-hens) or too heavy with > + 10% of target weight (H-hens). Using a general linear mixed model, potential influencing factors on the hens’ plumage and skin condition were evaluated. Results: The results showed that most investigated hens (74.9%) were categorised as such with no great deviation from target weight (G-hens: mean 1,823.0 ± 198.9 g), while L-hens made up 13.5% (mean 1,569.9 ± 192.7 g) and H-hens 11.6% (mean 2,097.4 ± 205.7 g). The statistical model on plumage damage revealed statistically significant effects of the laying phase, the season, the weight group with relation to the target weights (WTW) and the colour of plumage, while the housing system showed no effect. The season and laying phase were also found to have a significant effect on the sum of skin damage in the statistical model. Conclusion: As the weight classes with relation to the target weights assigned in the statistical model had an influence on the sum of plumage damage, and the animals from the group with the smallest deviations from the recommendations (G-hens) also had the lowest number of animals with plumage damage over the entire laying period, the results highlight the importance of good weight management in laying hen husbandry. Given the increased problems documented for the lighter animals in the L-hen group, the question remains as to what the trigger was and what the cause was: insufficient weight or existing plumage and/or skin damage.

This retrospective report investigated whether starting racehorses’ training and racing early is associated with a less successful and a shorter racing career. The data of 600 Thoroughbred racehorses from the German Racehorse Association’s archiving programme were evaluated. The horses were classified into three groups regarding their different ages when starting training and racing: early training (16–24 months old)/early racing (two years old); early training/late racing (>two years old); and late training (25–30 months). Statistical models investigated effects on the horses’ length of career. The results showed that the length of their racing career was influenced by sex; geldings showed the longest career as they do not enter breeding programmes, and were analyzed separately. Geldings entering training early, with their first race at two years old, showed higher ratings and a similar length of racing career than those with their first race at three years old or more. Thus, early racing appeared to have had no negative effect on the length of the racing career or perseverance in racing in the geldings investigated. Further studies researching training effects and physiological resilience should consider alternative explanations for racing selection criteria (e.g., early maturation advantage and prior unsoundness) and the reason for ending a racing career.

A commercial three-stage scrubber of a pig barn usually used to reduce ammonia, odour and dust was investigated regarding the reduction of indicator bioaerosols (mesophilic bacteria, haemolytic streptococci, methicillin-resistant Staphylococcus aureus, endotoxins as well as molds and yeasts). The bio-scrubber stage (third stage), was filled half with wood chips and half with paper pads as an alternative material in order to compare the reduction rates. Air samples were taken simultaneously with emission impingers from the untreated air, downstream of the acid scrubber (second stage) and downstream of the two bio-scrubber halves (third stage). The total reduction rate of indicator bacteria was at least 93% throughout all stages. However, both materials in the bio-scrubber stage significantly reduced an additional portion of the bioaerosols and therefore contributed to the overall reduction. This applied equally for endotoxins downstream of the wood chips half. In contrast, the cultivable mold and yeast numbers were not significantly reduced and increased downstream of the wood chips. Considering the reduction of potentially pathogenic bacteria, resistant bacteria and endotoxins of approximately log₁₀, it can be concluded that three-stage scrubbers can mitigate the risk of harmful bioaerosol emissions for residents and animals on neighbouring farms. In terms of the reduction of microorganisms, paper pads can be used as an alternative material to wood chips in the bio-scrubber stage.

This study investigated variations in assessing potential pecking injuries in turkey hens when annotating image excerpts. Three observers (OBS1, OBS2, OBS3) with different levels of previous knowledge - one with experience in pecking injuries in turkeys and two computer science students - rated a total of 24,912 image excerpts. The image excerpts were evaluated in work packages (2,076 images each) and were classified by the observers as either head injury (HI), skin injury in the feathered area of the body (SI), or no injury (NI). Two observers evaluated three packages (OBS1, OBS2: 6,228 image excerpts each) and OBS3 annnotated six work packages (12,456 excerpts). The percentage of the classifications in the chronological sequence of the observations was analyzed. Inexperienced observers (OBS2 and OBS3) both classified an average of 13% of the shown images as HI, 70% as SI, and 17% as NI. On average, OBS1 classified 12% of the images as HI, 60% as SI, and 28% as NI. Throughout the study, all observers classified more recordings into the NI class. Particularly, OBS1 with the most experience in evaluating pecking injuries showed a different assessment by rating more images (plus 5%) as showing NI over time (OBS2: plus 0.7%; OBS3: plus 2.2%). This result raises questions about whether divergent assessments always occur in repeated judgments and how this effect can be avoided.

Footpad dermatitis (FPD) is characterized by lesions on the plantar region of the footpad. It is one of the most common foot health problems and welfare issues mainly described for broilers and turkeys. This retrospective study aimed to evaluate the presence of this footpad disorder in laying hens as well as to identify typical risk factors for FPD during the laying period. Data were collected from 39 German laying hen flocks visited up to 16 times during production, where the housing system, flock size, age of flock, season, litter type and quality as well as hens' foot health were recorded in 30–200 randomly selected animals/visit using a four‐point scoring system (FPD‐Score 0–3). In total, 15,448 randomly selected laying hens were scored and classified, recording the highest degree of FPD per animal as well as whether FPD was detected in one or both of its feet. Of the hens examined, 78.9% showed no alterations, 18.6% showed slight ones, 2.2% moderate alterations, and 0.3% showed severe FPD. In the animals related to FPD (n = 3253), 48.0% of the hens showed an alteration in one foot and 52.0% in both feet. While few animals showed FPD at the first two visits (AF0, AF1), the percentage of animals related to FPD increased at the laying peak (~28th week of life). At the end of the laying period, 34.4% of the hens showed at least slight alterations (n = 955/2776). The results of the statistical analysis showed that the FPD‐Score was statistically affected by the type of litter, the season, and the age of flock (all P < .0001), while the quality of litter at the time of visit (P = .0940), the housing system (P = .2696), and flock size (P = .8776) were not related to FPD. In summary, this study detected that more than a third of the animals examined showed alterations in their footpads at the end of the laying period. Such changes in foot health occurred from the laying peak and increased to the end of the laying period. In addition to the age of the hens, the type of litter and the season were determined as potential risk factors. Moreover, this study shows how common this foot health problem is, not only in turkeys and broilers but also for laying hens.

This study analyzed trends of enthalpy and the temperature–humidity index (THI) over a period of 50 years in outer air, which lead to severe heat stress in turkeys. Weather station data from 15 German districts with high densities of turkey production were used to investigate the heat input into the barns. Therefore, the parameters of enthalpy and THI with specified thresholds were used for heat stress assessment. Trends in extreme weather situations where these thresholds were exceeded were analyzed and tested for significance using the Mann–Kendall test. In all districts, the heat load increased between 1973 and 2022 for both parameters. Statistically significant heat stress trends were found in 9 of the 15 districts for enthalpy and 14 out of 15 districts for THI. Thus, the established THI thresholds seem to be more sensitive for the detection of heat stress than the chosen enthalpy values. As heat stress is an important issue and a rising concern in times of climate change, farmers and constructors of farm animal facilities should take this into account in future sustainable work.