Keel Bone Deviations Research Articles

Perch use in 11-wk-old turkey hens: impact on performance, health, and behavior

Commercial turkeys are traditionally reared in floor barns, however, like most poultry species, turkeys display a natural desire to perch when given the opportunity. Perch use has typically been evaluated in laying hens, however due to size, weight, and postural differences, turkeys may have different preferences in perch design. The objectives were to examine perching preferences of turkey hens reared to 11 wk, as well as to examine the impact of perch use on hen health and performance. Nicholas Select (n=620) 11-d old turkey hens were randomly allocated to 20 pens (4 pen replicates/treatment) and assigned 1 of 5 perch design treatments (no perch (NP), 5 cm round dowel (5Rnd), 5 × 5 cm (5Sq), 10 × 5 cm (10Rec), or 15 × 5 cm (15Rec)). Data were analyzed via ANOVA as a complete randomized design, with significance declared when P≤0.05. Perch design did not affect hen performance or keel bone deviations and no fractures were found. Perching treatment had no effect on gait or footpad score at wk 7. At wk 11 gait scores were poorer in NP hens compared with 5Rnd (P=0.04) and footpad scores were poorer in NP hens compared with 15Rec (P=0.02). There were more turkey hens on the perch, as perch width increased at both 9 and 11 wk of age, demonstrating a preference for wider and flat perches. The results of this study demonstrate that turkeys will utilize perches when given the opportunity, with no detrimental effects seen on performance or bird health.

Japanese quails (Coturnix Japonica) show keel bone damage during the laying period-a radiography study.

Keel bone damage is an important welfare issue in laying hens and can occur with a high prevalence of up to 100% of hens within one flock. Affected hens suffer from pain. Although multiple factors contribute to the prevalence and severity of keel bone damage, selection for high laying performance appears to play a key role. With up to 300 eggs/year, Japanese quails show a high laying performance, too, and, thus, may also show keel bone damage. However, to our knowledge, there are no scientific results on keel bone damage in Japanese quails to date. Therefore, the aim of this study was to assess whether keel bone fractures and deviations occur in Japanese quails and to obtain more detailed information about the development of their keel bone during the production cycle. A group of 51 female quails were radiographed at 8, 10, 15, 19, and 23weeks of age. The X-rays were used to detect fractures and deviations and to measure the lateral surface area, length, and radiographic density of the keel bone. In addition, the length of the caudal cartilaginous part of the keel bone was measured to learn more about the progress of ossification. At 23weeks of age, quails were euthanized and their macerated keel bones assessed for fractures and deviations. Both keel bone deviations and keel bone fractures were detected in the Japanese quails. In the 23rd week of age, 82% of the quails had a deviated keel bone as assessed after maceration. Furthermore, there was a decrease in radiographic density, lateral surface area, and length of the keel bone between weeks of age 8 and 19. This could indicate a general loss of bone substance and/or demineralization of the keel bone. Our study shows that keel bone damage is not only a problem in laying hens but also affects female Japanese quails.

Influence of keel impacts and laying hen behavior on keel bone damage

Keel bone damage, which presents as fractures and/or deviations of the keel, has been detected in laying hens housed in all types of systems. Factors leading to keel bone damage in hens housed with limited vertical space, such as those housed in furnished systems, are not well understood, and are the topic of this study. Ten focal hens from each of 12 furnished cages (4 rooms of 3 cages) were fitted with keel mounted tri-axial accelerometers. Their behavior was video recorded continuously over two 3-wk trials: the first when the hens were between 52 and 60 wk of age, and the second approximately 20 wk later. The integrity of each hen's keel was evaluated at the start and end of each 3-wk trial using digital computed tomography. We identified predominant behaviors associated with acceleration events sustained at the keel (collisions, aggressive interactions and grooming) by pairing accelerometer outputs with video data. For each recorded acceleration event we calculated the acceleration magnitudes as the maximum summed acceleration recorded during the event, and by calculating the area under the acceleration curve. A principle components analysis, which was used as a data reduction technique, resulted in the identification of 4 components that were used in a subsequent regression analysis. A key finding is that the number of collisions a hen has with structures in her environment, and the number of aggressive interactions that a hen is involved, each affect the likelihood that she will develop 1 or more fractures within a 3-wk time span. This relationship between hen behavior and keel fracture formation was independent of the magnitude of acceleration involved in the event. Observed behavior did not have an impact on the formation of keel bone deviations, further supporting reports that the mechanisms underlying the 2 types of keel bone damage are different.

Shape and fractures of carina sterni in chicken genotypes with different egg deposition rates reared indoor or free-range

Commercial laying hens have high frequency of damage to the keel bone (KB), which causes negative effects on health and welfare. KB damage may consist in fractures (KBF) and deviations (KBD). The aim of the present study was to compare the KB shape, by means of Geometric Morphometric, and the occurrence of fractures in different chicken genotypes reared either free-range (FR) or in enriched cages. Moreover, the relationship between KB shape, genotype and rearing system was analysed. Sixty birds/genotype (2 Italian local breeds, Bionda Piemontese and Robusta Maculata, their crossbreeds with Sasso and Lohmann Brown) were used. All the hens fed the same commercial feed throughout the trial. Body weight, egg production, feed intake and mortality were recorded from 25 to 66 weeks of age. Ca intake (IN) and output (OUT) were estimated and Ca OUT/IN was calculated. FR affected the occurrence of KB deviations but not the shape, whereas the fractures were mainly affected by genotype. Local breeds had a lower prevalence of KBF with similar level of KBD but with different shapes. Crossbreeds seemed to be a suitable compromise between egg deposition rate and occurrence of KB damages.

How are they really doing? Animal welfare on organic laying hen farms in terms of health and behaviour

ABSTRACT 1. The present study describes the current welfare situation on commercial organic laying hen farms in Sweden in terms of indoor environment, bird health and behaviour. 2. Organic laying hen farms (n = 11) in Sweden were visited for one day each. The farm visits were performed at the end of lay and involved farmer interviews, indoor environment assessments, behavioural observations and tests and clinical examinations in one flock per farm. 3. In 95% of all human avoidance distance test trials performed, the hens distanced themselves from the observer before the test was completed. Median number of birds per flock approaching during a novel object test (n = 4 trials per flock) was 2 (0-9). These results may indicate a high level of fear of humans and general fearfulness among the hens. 4. Plumage damage was especially prevalent and most severe on the breast and belly, tail and wings, with median prevalence of moderate-severe damage of 96% (84–100), 96% (72–100) and 98% (94–100), respectively. Median prevalence of keel bone deviations was 67% (32–84) with 3% fractures (0–8). Median prevalence of breast skin lesions was 57% (10–74). There was a significant positive association between breast skin lesions and keel bone deviations (P = 0.02) and foot pad hyperkeratosis (P < 0.001). Median prevalence of severe hyperkeratosis was 33% (8–96), with prevalence being significantly lower where litter depth was thicker (P = 0.003). More dust bathing events were observed in flocks where litter depth was thicker (P = 0.007). 5. The present study contributes with updated knowledge of laying hen welfare on organic farms in Sweden. The results confirm the findings of previous on-farm studies, demonstrating that important issues, including keel bone damage and severe feather pecking, remain in need of attention to ensure the welfare of laying hens in future commercial egg production.

Effects of keel bone deviation on post-peak egg production in a commercial laying hen flock with different breast condition

This study was made to investigate the effects of breast condition and keel bone deviations on post-peak egg production of a commercial laying hen housed in a multi-tier conventional battery cage. The birds divided into two groups according to presence of keel bone deviation at first. Then the birds further divided into two groups according to breast condition as well developed or relatively well developed. The laying hens were kept under identical management conditions for commercial laying hens during the study. Data about daily egg production, feed intake, mortality and egg weight was collected from 62 to 77 weeks of age in the groups. There were no significant effects of keel bone deviation on body weight and egg weight of the layer hens. The initial and final body weight of the birds are significantly different between the breast condition groups (P

A tagged visual analog scale is a reliable method to assess keel bone deviations in laying hens from radiographs.

Laying hens often suffer from keel bone damage (KBD) that includes pathologies with different etiologies, like diverse forms of fractures and deviations. Since KBD is a problem in all countries and housing systems, methods for the assessment of deviations are urgently needed. Comparisons between genetic lines and between studies are important to detect underlying mechanisms. Field researchers often use palpation as a low-cost and feasible technique for the assessment of KBD. In contrast to palpation, radiography is effective and highly precise at least in detecting keel bone fractures. The aim of this study was to: i) develop a scoring system to assess keel bone deviations from radiographs, ii) to assess inter- and intra-observer reliability of this scoring system, and iii) to investigate whether fractures and deviations of the keel are correlated. In total, 192 hens were used for the investigation. Digital radiographs were taken and evaluated for all hens after slaughter. We developed a tagged visual analog scale with two extreme images as anchors and four intermediate tags, resulting in six images representing the range from "no deviation" to "highly deviated" on a 10 cm line. Eleven participants scored 50 radiographs of keels with varying degree of severity, whereas five images were scored twice to assess intra-observer reliability. Intraclass correlation coefficient for inter-observer reliability was 0.979 with a confidence interval of 0.968 < ICC < 0.987 (F49,268 = 54.2, p < 0.0001). Intraclass correlation coefficient for intra-observer reliability was 0.831 with a confidence interval of 0.727 < ICC < 0.898 (F54,55 = 10.8, p < 0.0001). Individual intra-observer reliability ranged from 0.6 to 0.949. The Spearman correlation showed a strong positive correlation of fractures and deviations (s roh= 0.803, p < 0.001). The tagged visual analog scale could be a reliable instrument for the scoring of keel bone deviations. Our results support the assumption that the majority of highly deviated keels suffer from fractures as well. Further research is needed to investigate the correlation of palpation scores with the evaluation on radiographs.

Keel bone fractures are more prevalent in White Leghorn hens than in Red Jungle fowl hens-A pilot study.

Fractures and deviations to the keel bone are common in commercial laying hens, with reported variations in occurrence across strains and breeds. The aetiology is not fully understood, however, modern genetics and selection for efficient egg production has been claimed to be important factors for the keel bone fractures. To explore this further, we investigated keel bones from two different breeds, representing different degrees of selection for egg production: Red jungle fowl (n = 82), and White Leghorn (n = 32), where the latter is a selected laying breed which is the origin for many modern laying hen hybrids. Keel bones from a total of 116 birds, 53 hens and 63 roosters, were examined by necropsy at 80 weeks of age. All birds were raised in modified aviaries in the same holding facility. Overall, 24.5% of the hens had one or more fractures to the keel, with a difference in the prevalence between hens from the two breeds (p<0.01): 10% (95% CI: 3.7–24%) in the Red Jungle fowl hens and 69% (95% CI: 37–90%) in the White Leghorn hens. No roosters, regardless of breed, had keel bone fractures. Mild to moderate keel bone deviations were present in 54% (95% CI: 25–80%) of the hens and 4.7% (95% CI: 0.5–30%) of the roosters, all White Leghorns.

Welfare Assessment of Two Free-range Laying Hen Flocks in Turkey

ABSTRACT This study aimed to determine the prevalence of keel bone deviations and feather damage of laying hens in two different free-range housing systems under commercial conditions. Both of the free-range systems had an indoor barn and an outdoor range area. The floor of the indoor barn consisted of litter and either perches (litter and perch, LP) or slats (litter and slats, LS). The hens of both flocks were raised under identical conditions in the same house during the rearing period and then divided and transferred to two different free-range housing systems for the laying period. Examinations were conducted on the flocks at the end of the production cycle. Hens from the LP group had a greater prevalence of keel bone deviation and feather damage compared to hens from the LS group. The highest percentage of severe feather damage was found in the back and tail body regions in both flocks. The findings of this study are based upon the evaluation of two Turkish laying flocks. Therefore further research with more replicates of these treatments is needed to reach a general conclusion.

Radiographic examination of keel bone damage in living laying hens of different strains kept in two housing systems.

A high prevalence of deviations and fractures of the keel bone is a widespread welfare problem in laying hens. The aim of this study was to experimentally investigate this multifactorial problem throughout the laying period and to compare the prevalence and severity in different layer lines and different housing systems. High performing white (WLA) and brown (BLA) pure bred layer lines and low performing white (R11, G11) and brown layer lines (L68) were kept in both single cages and a floor housing system. A total of 97 hens (19 or 20 from each line, respectively) were repeatedly radiographed in the 35th, 51st and 72nd week of age. Fracture prevalence increased with age (p<0.001). The proportion of deviated keel bone area increased only for caged BLA, WLA and R11 hens (p<0.05) and was significantly higher for caged WLA and R11 hens compared to floor-housed WLA and R11 hens in the 72nd week of age (p<0.05). In the 72nd week of age hens in the floor housing system showed significantly more fractures than hens kept in cages (p<0.05). Prevalence of keel bone deviations was significantly higher in the white layer line R11 but significantly lower in the white layer line G11 compared to both brown layer lines and WLA (p<0.05). Brown layers showed significantly more fractures than white layers (p<0.05) in the 51st and 72nd week of age. Within the brown layers there was a significantly lower prevalence of deviations (p<0.05) and fractures (p<0.05) in the low performing (L68) compared to the high performing line (BLA). Our results show a different development of keel bone damage in caged compared to floor-housed hens under experimental conditions. Additionally, they indicate genetic effects on keel bone damage.

The Influence of Keel Bone Damage on Welfare of Laying Hens.

This article reviews current knowledge about welfare implications of keel bone damage in laying hens. As an initial part, we shortly describe the different conditions and present major risk factors as well as findings on the prevalence of the conditions. Keel bone damage is found in all types of commercial production, however with varying prevalence across systems, countries, and age of the hens. In general, the understanding of animal welfare is influenced by value-based ideas about what is important or desirable for animals to have a good life. This review covers different types of welfare indicators, including measures of affective states, basic health, and functioning as well as natural living of the birds, thereby including the typical public welfare concerns. Laying hens with keel bone fractures show marked behavioral differences in highly motivated behavior, such as perching, nest use, and locomotion, indicating reduced mobility and potentially negative affective states. It remains unclear whether keel bone fractures affect hen mortality, but there seem to be relations between the fractures and other clinical indicators of reduced welfare. Evidence of several types showing pain involvement in fractured keel bones has been published, strongly suggesting that fractures are a source of pain, at least for weeks after the occurrence. In addition, negative effects of fractures have been found in egg production. Irrespective of the underlying welfare concern, available scientific evidence showed that keel bone fractures reduce the welfare of layers in modern production systems. Due to the limited research into the welfare implications of keel bone deviation, evidence of the consequences of this condition is not as comprehensive and clear. However, indications have been found that keel bone deviations have a negative impact on the welfare of laying hens. In order to reduce the occurrence of the conditions as well as to examine how the affected birds should be treated, more research into the welfare implications of keel bone damage is needed. Research should focus on effects of genetic lines, genetic selection, housing, and nutrition for the development, prevalence, and severity of these conditions, preferably conducted as longitudinal and/or transnational studies.

Welfare Consequences of Omitting Beak Trimming in Barn Layers.

Beak trimming is used worldwide as a method of reducing the damage to feathers and skin caused by injurious pecking in laying hens. However, beak trimming also causes some welfare issues as trimming the beak results in pain and sensory loss. Due to this dilemma, there is an ongoing discussion in several European countries about whether to ban beak trimming. In this study, we investigated the welfare consequences of keeping layers with intact beaks and examined for links between injurious pecking damage and keel bone damage on an individual level. A study was conducted on 10 commercial farms housing laying hens in the barn system. Each farm participated with a flock of beak-trimmed hens (T) and a flock of non-trimmed (NT) hens that were visited around 32 and 62 weeks of age. During visits, the condition of plumage, skin, feet, and keel bone of 100 hens was assessed. Mortality was recorded by the producers. NT flocks had a lower prevalence of hens with good plumage condition around 32 weeks of age (94.1 vs. 99.6%, P < 0.001) and a higher prevalence of hens with poor plumage condition at 62 weeks of age (63.6 vs. 15.2%, P < 0.001) compared with T flocks. The prevalence of hens with keel bone deviations, with both keel bone fractures and deviations and with body wounds, was higher in NT flocks compared with T flocks at both ages (P < 0.001). Accumulated mortality from placement to end of production tended to be higher in NT flocks compared with T flocks (14.2 vs. 8.6%; P = 0.06). The prevalence of keel bone damage was higher among hens with poor plumage condition than hens with moderate/good plumage condition (31.5 vs. 22.2%; P < 0.001). Thus, omitting beak trimming had negative consequences for the condition of plumage, skin, and keel bone, and tended to increase mortality, highlighting the risk of reduced welfare when keeping layers with intact beaks. In addition, injurious pecking damage was found to be positively linked to keel bone damage. The causal relation is unknown, but we propose that fearfulness is an important factor.

Mussel shells as an environment enrichment and calcium source for floor-housed laying hens

Feather pecking is still a behavioral problem in laying hen flocks, resulting in impaired welfare and economic losses. Environment enrichment, e.g., providing access to litter, to increase foraging behavior in laying hens has been shown to decrease feather pecking. This study investigated the effect of spreading crushed mussel shells (particle size 10 to 20 mm) in the litter area as an environment enrichment and source of calcium for layers receiving a commercial feed and for layers given a feed with 40% less calcium. These treatments were compared with a control involving hens given the commercial feed, but no mussel shells in the litter. The study included 900 Dekalb White layers housed in a single-tier floor system during a production cycle (20 to 72 wk of age). The mussel shells were consumed to a lower extent than predicted, resulting in calcium deficiency in hens fed the low-calcium diet. This in turn was evident as increased degree of keel bone deviations and lower eggshell breaking strength. Daily addition of crushed mussel shells to the litter for laying hens on a balanced or calcium-deficient diets did not generate any positive effects on bird feather cover, eggshell quality, production performance, or fearfulness. Hence, with the particle size of mussel shells used in this study, there was no indication of improved welfare due to environment enrichment.

Ramps and hybrid effects on keel bone and foot pad disorders in modified aviaries for laying hens

Non-cage systems provide laying hens with considerable space allowance, perches and access to litter, thereby offering opportunities for natural species-specific behaviors. Conversely, these typical characteristics of non-cage systems also increase the risk of keel bone and foot pad disorders. The aim of this study was twofold: 1) to investigate if providing ramps between perches (housing factor) reduces keel bone and foot pad disorders and 2) to test for genetic predisposition by comparing 2 different layer hybrids. In a 2 × 2 design, 16 pens were equipped either with or without ramps between perches and nest boxes (8 pens/treatment), and housed with either 25 ISA Brown or Dekalb White birds per pen (in total 200 birds/hybrid). Keel bone injuries and foot health were repeatedly measured via palpation and visual assessment between 17 and 52 wk of age and daily egg production was recorded. The relationships between the dependent response variables (keel bone and footpad disorders, egg production) and independent factors (age, ramps, hybrid) were analyzed using generalized linear mixed models and corrected for repeated measures. Ramps reduced keel bone fractures (F1,950 = 45.80, P < 0.001), foot pad hyperkeratosis (F1,889 = 10.40, P = 0.001), foot pad dermatitis (F1,792 = 20.48, P < 0.001) and bumble foot (F1,395 = 8.52, P < 0.001) compared to pens without ramps. ISA Brown birds sustained more keel bone fractures (F1,950 = 33.26, P < 0.001), had more foot pad hyperkeratosis (F1,889 = 44.69, P < 0.001) and laid more floor eggs (F1,1883 = 438.80, P < 0.001), but had fewer keel bone deviations (F1,1473 = 6.73, P < 0.001), fewer cases of foot pad dermatitis (F1,792 = 19.84, P < 0.001) and no bumble foot as compared to Dekalb White birds. Age, housing and hybrid showed several interaction effects. Providing ramps proved to be very effective in both reducing keel bone and foot pad problems in non-cage systems. Keel bone and foot pad disorders are related to genetic predisposition. These results indicate that adaptation of the housing systems and hybrid selection may be effective measures in improving laying hen welfare.

Risk factors associated with keel bone and foot pad disorders in laying hens housed in aviary systems

Aviary systems for laying hens offer space and opportunities to perform natural behaviors. However, hen welfare can be impaired due to increased risk for keel bone and foot pad disorders in those systems. This cross-sectional study (N = 47 flocks) aimed to assess prevalences of keel bone and foot pad disorders in laying hens housed in aviaries in Belgium to identify risk factors for these disorders and their relation to egg production. Information on housing characteristics and egg production were obtained through questionnaire-based interviews, farm records, and measurements in the henhouse. Keel bone (wounds, hematomas, fractures, deviations) and foot pad disorders (dermatitis, hyperkeratosis) were assessed in 50 randomly selected 60-week-old laying hens per flock. A linear model with stepwise selection procedure was used to investigate associations between risk factors, production parameters, and the keel bone and foot pad disorders. The flock mean prevalences were: hematomas 41.2%, wounds 17.6%, fractures 82.5%, deviations 58.9%, hyperkeratosis 42.0%, dermatitis 27.6%, and bumble foot 1.2%. Identified risk factors for keel bone disorders were aviary type (row vs. portal), tier flooring material (wire mesh vs. plastic slats), corridor width, nest box perch, and hybrid. Identified risk factors for foot pad disorders were aviary type (row vs. portal), free-range, and hybrid. Percentage of second-quality eggs was negatively associated with keel bone deviations (P = 0.029) at the flock level. Keel bone and foot pad disorders were alarmingly high in aviary housing. The identification of various risk factors suggests improvements to aviary systems may lead to better welfare of laying hens.

Early Onset of Laying and Bumblefoot Favor Keel Bone Fractures.

Simple SummaryNumerous studies have documented a high prevalence of keel bone fractures in laying hens. In this longitudinal study, 80 white and brown laying hens were regularly checked for keel bone deviations and fractures while egg production was individually monitored. About 62% of the hens had broken keel bones at depopulation. More new fractures occurred during the time when laying rates were highest. Hens with broken keel bones at depopulation had laid their first egg earlier than hens with intact keel bones. All birds with bumblefoot on both feet had a fracture at depopulation.Numerous studies have demonstrated influences of hybrid, feed, and housing on prevalence of keel bone fractures, but influences of behavior and production on an individual level are less known. In this longitudinal study, 80 white and brown laying hens were regularly checked for keel bone deviations and fractures while egg production was individually monitored using Radio Frequency Identification (RFID) from production until depopulation at 65 weeks of age. These focal birds were kept in eight pens with 20 hens per pen in total. About 62% of the hens had broken keel bones at depopulation. The occurrence of new fractures was temporally linked to egg laying: more new fractures occurred during the time when laying rates were highest. Hens with fractured keel bones at depopulation had laid their first egg earlier than hens with intact keel bones. However, the total number of eggs was neither correlated with the onset of egg laying nor with keel bone fractures. All birds with bumblefoot on both feet had a fracture at depopulation. Hens stayed in the nest for a longer time during egg laying during the ten days after the fracture than during the ten days before the fracture. In conclusion, a relationship between laying rates and keel bone fractures seems likely.

The effect of perch availability during pullet rearing and egg laying on musculoskeletal health of caged White Leghorn hens

A major skeletal problem of conventionally caged hens is increased susceptibility to osteoporosis mainly due to lack of exercise. Osteoporosis is characterized by a progressive decrease in mineralized structural bone. Whereas considerable attention has been given to enriching laying cages, little research has been conducted on providing caged pullets with furnishments, in particular perches. The objective of the current study was to determine if metal perches during all or part of the life cycle of White Leghorns affected hen musculoskeletal health, especially at end of lay. Treatments during the pullet phase (hatch to 16.9 wk) entailed cages with and without perches. Four treatments were used during the laying phase (17 to 71 wk of age). Treatment 1 chickens never had access to perches at any point during their life cycle, typical of egg industry practices in the United States for conventional cages. Treatment 2 chickens had access to perches only during the egg-laying phase, which was from 17 to 71 wk of age. Treatment 3 chickens had access to perches only during the pullet phase (0 to 16.9 wk of age). Treatment 4 chickens had perch access throughout their entire life cycle (0 to 71 wk of age). Musculoskeletal health was assessed by measuring muscle weights, bone mineralization, bone fracture incidence, and keel bone deviations. Muscle deposition of 71-wk-old hens increased when given access to perches as pullets. Bone mineralization of 71-wk-old hens also increased if given perch access as adults. However, the disadvantage of the adult perch was the higher incidence of keel deviations and keel fractures at end of lay. The increase in bone mineralization of the keel bone as a result of perch access during the pullet and laying phases was not great enough to prevent a higher incidence of keel bone fractures at end of lay. Perch redesign and placement of perches within the cage to minimize keel fractures and deviations are possible solutions.

Pressure load on keel bone and foot pads in perching laying hens in relation to perch design

The provision of perches in housing systems for laying hens is meant to improve hens’ welfare by allowing a more natural behavior repertoire. However, the use of perches is associated with welfare problems, such as keel bone deviations and foot pad lesions, that may possibly result from high mechanical pressure load during extended perching activities. The aim of this study was to analyze peak force and contact area of hens’ keel bones and foot pads on solid test perches of square, round, and oval shape with 3 different diameters each (experiment 1) and on commercially used perches (round steel tube, 2 sizes of mushroom-shaped plastic, and flattened round plastic) together with 2 prototypes of soft, round polyurethane perches (experiment 2). Test perches were covered with a pressure sensor film and 36 laying hens (18 Lohmann Selected Leghorn, 18 Lohmann Brown) were consecutively placed on each perch in an experimental cage during nighttime. Peak force (N/cm2) and contact area (cm2) were measured while hens were sitting and standing on the different test perches. Pressure peaks on the keel bone were approximately 5 times higher compared with single foot pad. On square perches, keel bone peak force was lower (P < 0.05) and contact area was larger (P < 0.001) compared with round and oval perches. In addition, peak force on foot pads in standing hens was higher on square perches (P < 0.05) compared with oval perches. Perch size did not affect peak forces on keel bones in sitting hens and foot pads in standing hens (experiment 1). On prototype perches, peak force on the keel bone was lower and contact area was larger compared with all commercial perches tested (P < 0.001). Peak force on foot pads was lower on prototype perches compared with steel perches (P < 0.01; experiment 2). Perches with a soft surface may possibly reduce keel bone and foot pad welfare problems in perching laying hens.

Results of the Animal Needs Index (ANI-35L) compared to animal-based parameters in free-range and organic laying hen flocks in Austria

AbstractThe aim of this study was a comparison of Animal Needs Index (ANI) data, derived from annual inspections by a control agency, with data collected from 164 selected on-farm flocks concerning feather damage, injuries, egg production, mortality, bodyweight, foot pad dermatitis, keel bone deviations and reactions towards humans (eg flock showed marked avoidance when the observer walked through the hen-house [yes/no]).Analysis of data showed a low number of significant correlations with total ANI scores and category scores: 1) Locomotion, 2) Social interaction, 3) Flooring, 4) Light, air and noise and 5) Stockmanship. Correlations found were low and total ANI score showed only a positive correlation with egg production at week 52. Category 3 scores correlated positively with egg production at week 70 and negatively with the percentage of hens with featherless areas and total pecking injuries. Category 5 scores showed positive correlations with egg production at week 52 as well as week 70 and negative correlations with mortality at week 52, the percentage of hens with featherless areas, pecking injuries &lt; 0.5 cm and total pecking injuries.Flocks showing marked avoidance had a lower total ANI score and lower category 3 and category 5 scores.In conclusion, welfare-related animal-based parameters are poorly reflected by the ANI-35-L/2001. To assess animal welfare more adequately, animal-based parameters have to be considered additionally in a welfare assessment scheme.

Health of Laying Hens in an Aviary System over Five Batches of Birds

Mortality and health were studied in laying hens kept in an aviary system on a practical scale. All management inputs were done by university staff. Five batches of birds (trials) during a period of 6 years with approximately 4,700 birds per trial were included in the study. The aviary was a three-tiered "Marielund" system divided into 4 pens. Three hybrids, reared on litter with access to perches, were used; Lohmann Selected Leghorn (LSL), Lohmann Brown (LB) and an experimental cross (SLU-1329). The hens were not beak-trimmed. The stocking density was 17 hens/m2 ground floor. Mortality varied between pens and between batches, ranging from normal rates of 3.4% to 7.8%, except in LSL in Trial 2 and LB in Trial 3 where it was much higher (15.6% and 20.9%, respectively). The dominating causes of total mortality were salpingitis and cannibalism. Coccidiosis and lymphoid leucosis contributed significantly to mortality in Trial 2. An infestation with fowl mites (Dermanyssus gallinae) occurred in Trial 1. Feather loss was most severe in LB. Keel bone deviations were recorded at increasing levels by age. Foot abscesses occurred more frequently at 35 weeks than at 55 weeks. LSL was more severely affected than LB and SLU-1329.