Vocalisations and acoustic parameters of flock noise from feather pecking and non-feather pecking laying flocks

1. In this study, the calling rates of vocalisations known to indicate distress and aversive events (Alarm calls, Squawks, Total vocalisations) and acoustic parameters of flock noise were quantified from feather and non-feather pecking laying flocks. 2. One hour of flock noise (background machinery and hen vocalisations) was recorded from 21 commercial free-range laying hen flocks aged > or =35 weeks. Ten of the flocks were classified as feather pecking (based on a plumage condition score) and 11 as non-feather pecking. 3. Recordings were made using a Sony DAT recorder and Audio-Technica omni-directional microphone, placed in the centre of the house-1.5 m from the ground. Avisoft-SASlab Pro was used to create and analyse audio spectrograms. 4. There was no effect of flock size or farm on call/s or acoustic parameters of flock noise. However, strain had an effect on the number of Total vocalisation/s; the Hebden Black flock made more calls than Lohmann flocks. Feather pecking flocks gave more Squawk/s and more Total vocalisation/s than non-feather pecking flocks. Feather pecking did not explain variation in alarm call rate or, intensity (dB) and frequency (Hz) measures of flock noise. 5. The differences between Squawk and Total vocalisation call rates of feather and non-feather pecking flocks are a new finding. An increase or change in flock calling rate may be evident before other conventional measures of laying hen welfare such as a drop in egg production or increase in plumage damage, thus enabling farmers to make management or husbandry changes to prevent an outbreak of feather pecking.     

Importance of the rearing period for laying hens in alternative systems

Feather pecking and cannibalism are still major problems in alternative systems for laying hens. Literature and practical experience indicate that unfavourable rearing conditions might be important risk factors for the occurrence of these behavioural disturbances during the laying period.Typical rearing conditions of laying hens from 50 rearing units in Germany and Austria are presented. Obvious risk factors during rearing for feather pecking and cannibalism during the laying period were found. Most flocks were kept under high stocking density (mean: 15 pullets per m' useable area) and some flocks had access to litter only after the second week of life or access to raised perches after the fourth week of life. Plumage condition of pullets and laying hens varied widely in non-beak-trimmed as well as in beak-trimmed flocks.The percentage of pullets with damaged plumage was higher in beak-trimmed than in non-beak-trimmed flocks (medians: 53 % versus 30 %, p = 0,022). In laying hens there was a higher percentage of hens with plumage damage in non-beak-trimmed flocks compared to beak-trimmed flocks (medians: 23 % versus 50 %, p = 0,007). Data analysis will be continued, especially with regard to particular risk factors.     

Influence of housing system and design on bone strength and keel bone fractures in laying hens

The main objectives of the study were to provide an accurate assessment of current levels of old breaks in end-of-lay hens housed in a variety of system designs and identify the important risk factors. Sixty-seven flocks housed in eight broad subcategories were assessed at the end of the production period. Within each flock, the presence of keel fractures was determined and the tibia, humerus and keel bones dissected for measurement of breaking strength. For each house, variations in internal design and perching provision were categorised and the effective heights of the differing structures recorded. All systems were associated with alarmingly high levels of keel damage although variation in mean prevalence between systems was evident with flocks housed in furnished cages having the lowest prevalence (36 per cent) despite also having significantly weaker bones and flocks housed in all systems equipped with multilevel perches showing the highest levels of damage (over 80 per cent) and the highest severity scores.     

Investigation of palpation as a method for determining the prevalence of keel and furculum damage in laying hens

Old breaks of the keel and furculum were identified by palpation in 500 end-of-lay hens from 10 flocks housed in free-range and barn systems, and the results were compared with the results obtained by a full dissection and inspection. The method was considered to be sufficiently precise to be used as a diagnostic tool although people using it would need to be trained. The results obtained by dissection indicated that 50 to 78 per cent of the birds in the flocks had breaks of the furculum and keel, but no other breaks of bones were detected.     

Prevalence of keel bone deformities in Swiss laying hens

The goal of this study was to evaluate the prevalence of keel bone deformities of laying hens in Switzerland. The keel bones of 100 end-of-lay hens from each of 39 flocks (3900 in total) were palpated. On average, 25·4% of the hens had moderately or severely deformed keel bones and the overall prevalence including slight deformities was 55%. 3. Variation between flocks was considerable. Thus, the prevalence of moderately or severely deformed keel bones ranged from 6 to 48%, and the overall prevalence including slight deformities ranged from 20 to 83%. Aviary housing was associated with a higher prevalence of total, and severe or moderate deformations, compared with floor pens. There were no significant differences in the number of deformities between the different plumage colours, hybrids or perch materials.     

Pathologic-anatomic investigations in laying hens in various housing systems]

Gross pathologic and histologic changes were investigated in a total of 1000 end-of-lay hens. Thirty animals were drawn from free range stocks, 270 from deep litter stocks, and 700 from caging systems. The following changes were evaluated with regards to housing systems: Pododermatitis, deformation of the keel bone and amputated beaks occurred primarily in free range hens. Deep litter hens also suffered from pododermatitis, keel bone deformation and amputated beaks in addition to pecking wounds. In caged hens severe fatty liver syndromes, injuries of the claws and inflammation of the feather follicles were mainly found. Furthermore, injuries and fractures due to handling and transport were almost exclusively found in caged hens. It has to be concluded that all of the investigated housing systems can predisposed hens to certain lesions. The documented changes--e.g. chronic inflammation, skelettal deformities and injuries--are painful and may lead to permanent alterations. Therefore, these changes should be condemned as conflicting with animal protection regulations.     

Effect of rearing factors on the prevalence of floor eggs, cloacal cannibalism and feather pecking in commercial flocks of loose housed laying hens.

1. Effects of rearing conditions on behavioural problems were investigated in a cohort study of commercial flocks of laying hens housed in 2 different loose housing systems. The sample population was 120 385 laying hens from 59 flocks of various hybrids at 21 different farms. 2. Logistic regression modelling was used to test the effects of selected factors on floor eggs, cloacal cannibalism and feather pecking. In addition to early access to perches or litter, models included hybrid, stocking density, group size, housing system, age at delivery, identical housing system at the rearing farm and at the production farm and, in models for floor eggs and cloacal cannibalism, nest area per hen. Odds ratios were calculated from the results of the models to allow risk assessment. 3. No significant correlations were found between the prevalence of floor eggs, cloacal cannibalism and feather pecking. 4. Access to perches from not later than the 4th week of age decreased the prevalence of floor eggs during the period from start-of-lay until 35 weeks of age, odds ratio 0-30 (P<0-001). Furthermore, early access to perches decreased the prevalence of cloacal cannibalism during the production period, odds ratio 0-46 (P=0.03). 5. No other factor had a significant effect in these models. Although it was not significant, early access to litter had a non-significant tendency to reduce the prevalence of feather pecking.     

Feather pecking in laying hens housed in free-range or furnished-cage systems on French farms

ABSTRACT

1. Beak trimming is currently used in France to avoid the negative consequences of severe feather pecking (SFP). However, this practice is controversial in terms of animal welfare, and forbidden in some European countries.

2. This study aimed to assess the prevalence of SFP in French laying hen farms, to describe how farmers manage this behavioural disorder and to better understand the risk factors involved.

3. A study was carried out from April 2015 to June 2016. Visits were paid to 79 flocks kept in furnished cages (FC) and 80 flocks in a free-range (FR) system. All the hens had trimmed beaks and were genotypically brown. The information collected included feather cover, skin damage, beak condition, farm and poultry house characteristics, livestock performance and management.

4. The prevalence of SFP in FC flocks was estimated at 32.9% (IC = 95%, [22.5; 43.3]) and the prevalence of cannibalism as 2.5% (IC = 95%, [0.7; 8.8]) at 70 weeks of age. The prevalence of SFP in FR flocks was estimated to be 23.8% (IC = 95%, [14.5; 31.1]) and the prevalence of cannibalism was 8.8% (IC = 95%, [4.3; 17.0]) at 61 weeks of age.

5. In FC flocks, SFP was associated with the combination of genotype, type and length of perches, cage area per hen, type of lighting, number of hens per cage and farm location. In FR flocks, feather cover was associated with use of the outdoor run, lighting programme, genotype, farm location and date of house construction.     

Pop hole use by hens with different keel fracture status monitored throughout the laying period

The aim of this work was to study the effect of keel fractures on the extent to which free-range hens access the range through pop holes. Over two consecutive laying periods (two production years) a total of 1100 individual birds from one half of a house, divided into four separated flocks, were caught at 25, 35, 45, 55 and 65 weeks, palpated to assess the prevalence and severity of keel fractures and tagged with RFID transponders. Their use of pop holes was subsequently monitored in some cases from week 25 to end of lay at 68 to 70 weeks. At regular intervals (every 10 weeks), the tagged birds were re-caught to assess changes in keel fracture prevalence and severity. The average percentage of birds with fractured keels at 25, 35, 45, 55, 65 and at end of lay (68 to 70 weeks of age) was 5.5, 25.5, 49, 63, 66.5 and 78.5, respectively, across both production years. The effect of keel score on pop hole use was modelled statistically, adjusting for weather conditions and age of the birds. There were significant effects of most of the weather variables recorded, as well as age of the bird, on use of pop holes and also a significant effect of keel score. Higher keel scores resulted in a reduction in pop hole use. A significant statistical interaction between keel score and ambient temperature revealed an accelerated reduction in use as the temperature decreased and keel score increased. It is concluded that the occurrence of keel fractures may affect the birds' ability or willingness to utilise the outdoor range provided by free-range housing systems, thereby reducing the potential welfare advantages of this type of housing.     

Pecking behaviour of laying hens in single-tiered aviaries with and without outdoor area

1. The objective of the present study was to examine the behaviour of laying hens in single-tiered aviaries with and without outdoor areas with particular reference to the proportion of each behaviour and the ways it changed. 2. In all, 144 interbred cross layers (WL/RIR cross-breed) were used. At the age of 16 weeks, the hens were divided at random into two groups and moved to single-tiered aviary (SA) and free-range systems (FR, SA with in addition an outdoor range area covered with clover) with 18 hens per pen. Behavioural observations were conducted before, during and after access to the range. 3. All behaviours using the beak (eating, grazing, drinking, preening, aggressive pecking, feather pecking, litter pecking, object pecking and mate pecking) were recorded as pecking behaviour. 4. While most of the FR hens spent their time outside foraging, the proportion of hens eating, preening, litter pecking, object pecking, aggressive pecking and feather pecking was higher in SA than in FR hens. 5. The proportion of hens performing pecking behaviour of all types was very similar in SA (61.7 +/- 2.0%) and in FR (64.0 +/- 0.8%). The proportion of hens performing overall pecking behaviour increased as pre-laying sitting decreased. 6. The proportion of hens feather pecking decreased in FR during access to range and a similar tendency was found for aggressive pecking. 7. In conclusion, the total proportion of hens pecking was almost the same regardless of whether an outdoor area was provided or not, but the incidence of different types of pecking behaviour differed between SA and FR. The risk of feather pecking in FR may be lower when an outdoor grazing area is provided, although further testing on a larger scale would be essential.     

Assessment of the behaviour and welfare of laying hens on free-range units

The aims of this study were twofold: to develop and test an animal-based protocol for the assessment of the physical and emotional elements of the welfare of laying hens on free-range units and to investigate the effects of different approaches to housing and management on the welfare of the birds. The protocol was tested on 25 free-range units for laying hens, each of which was visited on four occasions by one of five trained observers; further information about husbandry, health and productivity was gathered from interviews with the farmers. Measures of the birds' attitude included arousal, noise, flight distance and response to a novel object, measures of their activity included feather pecking, aggression and use of range, and measures of their physical welfare included mortality, body condition and egg quality. Increased arousal was associated with increased flight distance, greater reluctance to approach a novel object and higher levels of feather pecking and feather loss, but the correlation between pecking and feather loss was low. The birds maintained body condition throughout the period of lay. Neither body condition, feather pecking nor feather loss was affected by the extent of beak trimming. Estimated losses (deaths and culls) ranged from 1.8 to 21.4 per cent (median 6.95 per cent). Few birds showed signs of ill health, limb lesions or red mite infestation. No feature of building design had a significant effect on mortality, but there were consistent differences in the birds' attitude, behaviour and performance attributable to the type of floor and the presence or absence of perches, which suggested that the welfare of the hens was inferior when they were housed on plastic floors with no perches.     

Plumage colour and feather pecking in laying hens,a chicken perspective?

1. This study investigated whether feather damage due to feather pecking and bird behaviour were influenced by plumage colour in Oakham Blue laying hens (black, white, grey colour variants). The reflectance properties of feathers and spectral composition of light environments experienced by the hens were also examined. 2. Nine hundred and seventy-nine birds were inspected and scored for feather damage; 10.5 h of video recordings were examined to record feather pecking and bird behaviour. Feathers and light environments were measured using a USB-2000 spectrometer and DH-2000-CAL-DTH lamp. 3. Oakham Blue birds with white plumage had less feather damage due to feather pecking than black or grey birds. There was more severe feather pecking in the mornings than in the afternoon. White birds feather pecked severely more than black or grey birds, although there were no other behavioural differences between plumage colours. 4. White feathers reflected at a higher intensity than black or grey feathers. However, black and grey feather spectra were relatively flat and the contribution of UV wavelengths to plumage reflection was proportionally greater than that for white feathers. 5. Light intensity inside a poultry house was 100 x (UW/cm2/nm) less than on the range and there was low or no UV reflectance. Under the dim, artificial lights inside a poultry house, Oakham Blue hens with black and grey feathers may be less visible to conspecifics than white birds because their plumage reflects at a lower intensity. Furthermore, the lack of available UV light inside vs. outside and the higher contribution of UV reflectance to black and grey plumage may make black and grey birds appear more different inside the house than white birds. It is possible that this novel/unusual appearance may make black or grey Oakham Blue hens more susceptible to feather pecking.     

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.     

Welfare of layers housed in small furnished cages on Danish commercial farms: the condition of keel bone,feet, plumage and skin

1. An on-farm assessment of keel bone, feet, plumage and skin damage was conducted in layers in small furnished cages to evaluate welfare implications.

2. Thirteen farms participated, all housing Lohmann LSL layers in systems allowing 8 or 10 hens per cage.

3. Each flock was visited at three different ages: 32, 62 and 77 weeks. During each visit, 100 hens were examined for keel bone fractures and deviations, plumage damage, body wounds, foot pad lesions, bumble feet, missing toes and toe wounds.

4. A deterioration with age of the condition of the plumage and keel bone was found (P < 0.001). At 77 weeks of age, 16% of the birds had poor plumage, and 43% of the birds had keel bone damage. In contrast, foot pad lesions were most prevalent at 32 weeks of age (13%), whereas the other foot injuries and body wounds remained at a relatively low level throughout the three ages examined.

5. Prevention of damage to the keel bone, plumage and foot pads should therefore be considered when aiming to improve welfare of laying hens housed in small furnished cages.     

Levels of mortality in hens by end of lay on farm and in transit to slaughter in Great Britain

The average mortality for end of lay hens dead on arrival (DOA) was 0.27 per cent (median 0.15 per cent) in a survey of 13.3 million hens transported during 2009. A statistical model of the data indicated main risk factors for DOA to be slaughter plant, distance travelled and external air temperature, with longer journeys and low external air temperatures increasing the risk. Other highly significant risk factors (P<0.001) related to the condition of the birds on farm, where an increased risk of DOA was positively associated with poor feather cover, lower body weight, cumulative mortality of the flock and poor health (indicated by a high proportion of the load rejected at the plant for traumatic injury and disease state). However, the data indicate that by taking risk factors into consideration it is possible to transport hens up to 960 km with low losses in temperate conditions. Mean levels of on-farm mortality, during the laying period, for a total of 1486 flocks were significantly lower in cages (5.39 per cent) than in barn (8.55 per cent), free-range (9.52 per cent) or organic flocks (8.68 per cent) according to producer records a median of seven days before depopulation, with considerable variation between flocks in all systems.     

Environmental contamination and detection of Salmonella enterica serovar enteritidis in laying flocks.

Faecal, dust and other environmental samples were collected from the floors, droppings belts, egg-collection systems and other areas of 14 cage-layer flocks, 10 barn egg production flocks and seven free-range flocks, and cultured for Salmonella species. The distribution of the organism varied with its prevalence and with the vaccination status of the birds. No one sample type was found to be suitable for identifying all contaminated houses. Salmonella was also frequently found on egg-packing equipment and in samples from rodents and wild birds.     

Bacterial contamination of eggs and behaviour of poultry flocks in the free range environment

The free range production system is becoming more common in Australia and is expected to increase. Free range hens are exposed to more stressors in comparison to hens from barn and cage systems and it is suggested that stress can increase bacterial shedding on eggs. The aims of this study were to examine the level of total bacteria and Enterobacteriaceae populations, as well as the presence of Salmonella and Campylobacter, in eggs collected from two free range flocks on two different farms and to conduct longitudinal observations of the behaviour and welfare of hens in the free range production system. Hen age (weeks) was shown to have a significant effect (increase) on the level of total bacteria on the egg shell surface and in shell pores, as well as having an effect on feather condition score. As the hens aged, the frequency of external visual egg characteristics increased, as did feather condition score (where feather condition was poorer). These observations indicate areas which should be investigated further to improve the food safety of eggs and optimise the welfare of free range hens.     

Matched concurrent case-control study of risk factors for feather pecking in hens on free-range commercial farms in the UK

1. The aim of the study was to compare the management and husbandry of free-range flocks in the UK where feather pecking was either present (case) or absent (control). 2. One hundred flocks were enrolled into a concurrent case-control study: 50 where birds had recently started feather pecking, and 50 matched control flocks where birds of the same age had not started feather pecking. 3. Information was obtained from a detailed interview with the flock manager, and by direct inspection of the flock, house and range. 4. Initial univariate analyses revealed that case flocks were more likely to comprise ISA Brown than Lohmann, were more likely to be restricted from litter areas to prevent floor eggs, and were less likely to use the outside range. 5. Cluster analysis indicated that feather pecking was not associated with any particular husbandry system. 6. The only influential risk factor significant in the multivariable conditional logistic regression analysis was use of the outdoor range. The risk of feather pecking was reduced 9-fold in flocks where more than 20% of birds used the range on sunny days (odds ratio = 0.12). Use of the range was positively associated with the presence of trees and/or hedges on the range.     

Effect of foraging material and food form on feather pecking in laying hens

1. The aim was to test whether provision of foraging material and food form influence feather pecking and feather damage in laying hens. 2. From week 19 of age, 16 groups of 11 hens (white Lohman Selected Leghorn hybrids) were kept in pens with or without access to long-cut straw as foraging material and fed on either mash or pellets. 3. Foraging behaviour was increased in hens with access to straw and time spent feeding was increased in hens fed on mash. In addition, hens fed on mash had longer feeding bouts and higher rates of pecking at the food during feeding than hens fed on pellets. 4. There were interaction effects of foraging material and food form on both feather pecking and feather damage. High rates of feather pecking and pronounced feather damage were only found in hens housed without access to straw and fed on pellets. In groups characterised by high rates of feather pecking the hens also showed more severe forms of this behaviour. 5. Differences in the time budgets of hens kept in different housing conditions suggested that birds fed on mash used the food not only for feeding but also as a substrate for foraging behaviour. 6. In order to avoid problems with feather pecking it is recommended that laying hens are provided with foraging material and fed on mash.     

Feed particle selection and nutrient intake altered by pecking stone consumption and beak length in free-range laying hens

The present study investigated the effects of pecking stones on feeding behaviour of hens from 16 to 46 weeks of age. Eighteen flocks of Hy-Line Brown hens were housed in 2 commercial free-range housing systems. Farm A housed 10 flocks of beak trimmed (infrared beak treatment) hens in fixed sheds. Farm B housed 8 flocks of hens with intact beaks in mobile sheds. On each farm, flocks were equally assigned to control groups (no access to pecking stones) and treatment groups (access to pecking stones). Data were evaluated every 10 weeks. At each time point, 10 hens per flock were housed in individual pens, and each hen was provided with 250 g of mash diet and ad libitum water for 24 h. After 24 h, feed samples were collected and used to determine 24-h feed intake. Nutrient and particle selection was measured by subtracting nutrients and particles present in the leftover feed from the vaules obtained in the offered feed and expressed the change (Δ). In addition, pecking stone consumption was recorded for each flock. Data were analysed separately for each farm using fixed effects of pecking stone availability and hen age. Spearman's rho correlation coefficients and linear regression models were constructed to evaluate the relationship of beak length and pecking stone usage, discrete mean particle size (dMEAN) consumption (Δ dMEAN), and Δ nutrient intake. Hens with access to pecking stones consumed significantly lower quantities of large feed particles (>2.8 mm) on farm A (P = 0.029) and selected significantly more fine particles, on farm B (P = 0.013). Overall, positive relationships (P = 0.001) between beak length and pecking stone consumption, Δ dMEAN, and Δ phosphorus consumption were observed. In conclusion, pecking stone consumption resulted in reduced selection and consumption of feed particles in hens housed on both farms. Further research is warranted to investigate the effect of pecking stones on sensory innervation of the beak.