Providing elevated structures in the pullet rearing environment affects behavior during initial acclimation to a layer aviary

Spatial abilities of hens are particularly sensitive to development during early life. Experiences in pullet housing may have lasting consequences on adult hens' movements in cage-free environments. We tested whether opportunities to access elevated spaces during rearing improved hens' use of a multitiered aviary. Female Dekalb White pullets were reared in either floor pens (FL), single-tiered aviaries (ST), or 2-tiered aviaries (TT; n = 5 pens/environment) through 16 wk of age. Rearing structures were replaced with identical multitiered aviaries at 17 wk. The distribution of the flock within the aviary and the vertical transitions of 10 focal hens/pen across the aviary were determined from videos recorded during their first (D1) and seventh (D7) day of aviary access, as well as at 19, 23, and 27 wk of age. Prevalence of floor eggs was recorded weekly from 17 to 28 wk of age. On D1, more ST and TT hens utilized the aviary during the daytime (P = 0.0077), made more vertical transitions when searching for a roosting spot in the evening (P = 0.0021), and maintained a consistent distance traveled during transitions compared to FL hens (P = 0.02). These differences disappeared by D7, except that ST and TT hens continued to roost on the highest perches of the aviary more (P < 0.0001) than FL hens through 27 wk of age. FL hens laid more floor eggs than ST and TT hens for the first 2 wk of lay (P < 0.0001). The majority (97.9%) of vertical transitions was controlled. Uncontrolled transitions were highest at D1 and decreased by D7 (P = 0.0009) and were not affected by rearing (P = 0.33). The results suggest that hens reared with minimal height are hesitant to use the laying hen aviaries when they are first transferred. They acclimate within 1 to 2 wk, but continue to roost less in the highest accessible level.

Visitor engagement with zoo staff and interpretive demonstrations increases visitor stay time in two free-flight aviaries

Understanding how visitors spend time in zoo exhibits is important as zoological facilities work to enhance visitor experience and conservation education outcomes. We explored a variety of factors we hypothesized would influence visitor stay times in two aviaries at Disney's Animal Kingdom®. Within these aviaries, visitors could utilize educational materials, listen to staff-led demonstrations, or talks, view animal training sessions, or speak directly with animal care or education staff. We observed visitors and recorded the opportunities they utilized in the exhibit. Visitors to either aviary who conversed with exhibit-specific staff stayed between 67% and 89% longer than visitors who did not. In addition, visitors who used a bird guide while in either aviary stayed between 59% and 82% longer than those who did not. Those who listened to an animal care talk or engaged with a staff-led demonstration stayed between 50% and 68% longer than those who did not have the option to participate in such activities. This study provides insight into how exhibit offerings can influence visitor behavior. Implementing strategies used in this study to increase visitors' time in an exhibit may enhance visitor experience and improve learning outcomes.

Genetic parameter estimates for the use of an aviary with winter garden by laying hens

The behavioral activity of laying hens in an aviary is indicative of their welfare and health. Furthermore, hens' usage of the different locations within an aviary has been shown to influence laying performance and egg quality. For example, hens that spent a longer duration of time in the nest during laying were observed to have lower laying performance. Therefore, understanding genetics of laying hens' usage of the aviary could be important for predicting egg quality, production traits and health and welfare. The objectives of this study were to estimate genetic parameters for duration of time spent at different locations within the aviary and an adjacent winter garden using a multivariate repeatability model and to compare correlations between time spent in these locations. For this study, a total of 1,106 Dekalb white laying hens (Hendrix Genetics) were genotyped using a proprietary 60K SNP array. These hens had access to 5 different zones within the aviary, which included the top level tier, nest box tier, lower level tier, floor littered area and a winter garden. Hens were in the aviary for a total of 290 d and daily records of duration were collected for each hen visit to any location in the aviary, culminating in a total of 937,740 records. Heritability estimates ranged from 0.05 (0.01) to 0.28 (0.03) for the duration of time spent in the different zones. The lowest heritability was estimated for time spent at the lower level tier, while a higher heritability was estimated for time spent in the floor littered area. A moderately high negative genetic correlation of -0.59 (0.08) was observed between time spent in the top level tier and time spent in the floor littered area, while a favorable correlation of 0.37 (0.14) was found between time spent in the lower level tier and time spent in the winter garden. The findings of this study show that the duration of time spent at different zones within an aviary has genetic basis and could be used for selecting animals for better performance and higher welfare.

Factors affecting space use by laying hens in a cage-free aviary system: effect of nest lighting at pullet housing and of curtain nest color during laying

At 17 wk of age, 1,800 Lohman brown hens were housed in 8 pens of an experimental aviary system, specifically set up for the purposes of the present study, and kept until 26 wk without or with nest lighting (lights inside the nest 1.5 h before the lighting of the installation) for training in the nest use. Then, at 27 wk, 4 combinations of nest curtains were adopted to evaluate the effects on hens' distribution, that is, nests with red (RR) or yellow (YY) curtains at all tiers; nests with red and yellow curtains at the first and second tier, respectively (RY); or nests with yellow and red curtains at the first and second tier, respectively (YR). The use of enlightened compared to dark nests at housing increased the oviposition rate (P < 0.001) and decreased the rate of broken (P < 0.001) and dirty eggs (P < 0.05) from 27 to 45 wk, while increasing the rate of eggs laid inside the nests (P < 0.001). The presence of yellow nest curtains increased the rate of hens on the floor in pens YY and YR compared to pens RR and RY (35.3 and 35.5% vs. 34.1 and 33.3%, respectively; P = 0.05) and the rate of floor eggs in pens YR (2.23% vs. 1.63 and 1.65% in pens RR and RY; P < 0.05). In pens RY, a higher rate of eggs was always found on the second tier compared to the first one with the most inhomogeneous distribution compared to pens RR, YY, and YR (+10.8 vs. +3.4, +1.9, and +4.6 percentage points of eggs laid on the second tier compared to the first one, respectively). In conclusion, nest lighting at housing trained hens to the use of nests while improving egg production in terms of quantity and quality. The use of yellow curtains on nests moved hens between the different levels of the aviary but this was not associated with an increased nest use for laying.

Flock Factors Correlated with Elevated Mortality in Non-Beak Trimmed Aviary-Housed Layers

The use of non-cage housing systems for layers is increasing in Europe and elsewhere. Knowledge of factors that may affect mortality in these systems is important to be able to improve animal welfare, reduce mortality and enhance sustainability. The aim of this study was to investigate factors that may contribute to increased mortality in non-beak trimmed aviary-housed laying hens in Norway. A total of 39 non-beak trimmed commercial flocks (Lohmann LSL (n = 25) and Dekalb White (n = 14)) were visited between week 70 to 76 of life, and factors related to health, behaviour and management were recorded. Mean mortality in the flocks was 3% (range: 0.5−9%) and increased flock mortality was correlated with total feather loss (p < 0.05); feather loss on the breast (p < 0.02) and feather loss on the head (p < 0.003). There was an association between layer hybrid line and mortality (p = 0.055). Furthermore, a low positive correlation between mortality and dust level inside the barn was found (p < 0.04), showing that mortality was higher when dust level was also high. No correlation between mortality and the provision of environmental enrichment was found. In conclusion, this study found an association between flocks with elevated mortality (>3.0%) and increased feather loss which may indicate feather pecking. The results underline the importance of regularly assessment of plumage condition in commercial layer farms, as a tool to detect early signs of feather pecking in commercial aviary-housed layer flocks. This may help to target feather pecking before cannibalism breaks out.

Effect of Providing Environmental Enrichment into Aviary House on the Welfare of Laying Hens

This study aimed to determine the effects of providing environmental enrichment materials—pumice stone and alfalfa hay—to laying hens in the aviary system. A total of 2196 40-week-old Hy-Line Brown laying hens were randomly allotted to three treatment groups: (1) no enrichment (control; CON), (2) enrichment with pumice stone (PS), and (3) enrichment with alfalfa hay (HAY). Each treatment comprised four replicates of 183 hens each, and four of the same materials were provided per replicate. The experiment lasted for 26 weeks. Feed and water were provided ad libitum. As a result, the PS and HAY groups demonstrated increased egg production (p < 0.001). The HAY group showed a reduced rate of mislaid eggs (p < 0.01) and produced low egg weight and pale-yellow yolk (p < 0.05). Both enrichment materials decreased blood creatinine (CRE) or lactate dehydrogenase (LDH) in the blood and resulted in a significantly lower corticosterone (CORT) level (p < 0.05). However, the feather condition scores for the laying hens were similar across all treatments (p > 0.05). In summary, although pumice stone and alfalfa hay are effective in alleviating stress and improving the production of laying hens, additional environmental improvement studies are needed to contribute to reducing pecking behaviors in poultry farming.

Fatal Sarcocystis calchasi-associated meningoencephalitis in 2 captive vulturine guineafowl

Two captive vulturine guineafowl (Acryllium vulturinum) were presented with lethargy, hyporexia, weight loss, and progressive neurologic signs. One of the guineafowl was seropositive for Sarcocystis falcatula (1:50 dilution). Both guineafowl died within 5 d of presentation. Histologic examination revealed nonsuppurative meningoencephalitis with gliosis, associated with occasional schizonts in the neuropil. Using fresh-frozen brain tissue, PCR was performed to amplify the ITS1 RNA region and portions of the 18S ribosomal RNA gene (18S gene) and the 28S ribosomal RNA gene (28S gene). Analysis of nucleic acid sequences from the resulting amplicons indicated that Sarcocystis calchasi was the likely cause of disease. To our knowledge, S. calchasi-associated disease has not been reported previously in the order Galliformes.

Captive Psittacines with Chlamydia avium Infection

Avian chlamydiosis is an infection caused by obligate intracellular, gram-negative bacteria belonging to the Chlamydiaceae family. Birds can be hosts of several Chlamydia species, including Chlamydia avium, which has only been detected in pigeons and psittacine birds. In this study, depression, respiratory distress, and mortality were noted among psittacines belonging to a large aviary with 35 different avian species. On the basis of immunohistochemistry and PCR testing, chlamydiosis was diagnosed in affected birds. Gross and histopathologic lesions were mainly observed in the spleen and gastrointestinal tract. Chlamydia avium was detected in four psittacines by PCR, including two dead birds and two individuals exhibiting respiratory distress. Increased aspartate aminotransferase and lactate dehydrogenase values and anemia were consistently identified in affected birds. Administration of doxycycline, combined with hepatoprotectors and vitamins, was effective in stopping mortality and bacterial shedding.

Pecking Behavior in Conventional Layer Hybrids and Dual-Purpose Hens Throughout the Laying Period

To avoid the killing of surplus male layer chickens, dual-purpose hybrids are suggested as an alternative approach. These strains may offer additional advantages compared to conventional laying hens, for instance, a lower tendency to develop injurious pecking behavior. The aim of this study was to assess the behavior, with focus on pecking behavior, of conventional layers (Lohmann Brown plus, LB+) and dual-purpose hens (Lohmann Dual, LD). About 1,845 hens per strain with intact beaks were housed in four stable compartments in aviary systems. Video-based scan sampling of general behaviors and continuous observations of pecking behavior were carried out between 25 and 69 weeks of life. With the exception of "dustbathing" and "scratching," hybrid × time during the laying period affected all of the observed general behaviors [F _{(2, 89)} = 3.92-10.81, P < 0.001-0.05]. With increasing age, the LB+ hens performed more general pecking, more locomotion and less comfort and sitting behavior. General pecking and comfort behavior did not change over time in the LD hens, whereas inactive behaviors increased with age. During continuous observations, a significant hybrid x period interaction was found for all forms of pecking behavior [F _{(2, 89)} = 4.55-14.80, P < 0.001-0.05]. The LB+ hens showed particularly more severe feather pecking (SFP), which increased with age. In contrast, SFP remained exceptionally low in the LD hens throughout production. Therefore, dual-purpose hybrids should be considered as an alternative to both avoid the killing of surplus male chickens and the development of SFP in laying hen production.

Effects of Rearing Aviary Style and Genetic Strain on the Locomotion and Musculoskeletal Characteristics of Layer Pullets

Previous research indicates that the musculoskeletal development of pullets is improved when pullets are reared in aviaries compared to conventional rearing cages. However, there are considerable differences in rearing aviary design. To measure locomotion and musculoskeletal development of brown (n = 7) and white-feathered (n = 8) strains of pullets, 15 commercial flocks in three styles of rearing aviaries differing in structural complexity (n = 5 per style) were visited three times: 25.9 ± 6.67, 68.0 ± 4.78, and 112.1 ± 3.34 days of age. Locomotion (duration of standing, sitting, walking, running, flying, and rates jumping, flying, group running and walking) was analysed from videos recorded three times per day: at the beginning, middle, and end of the light cycle. Pullets for dissection were taken on visits 2 and 3. Pullets in the most complex system (style 3; S3) spent the most time locomoting throughout rearing (p < 0.05). Pullets in S3, particularly white-feathered strains, performed the highest rate of vertical transitions (p < 0.05). There were no differences in any of the proportional muscle weights between aviaries styles (p > 0.05) despite the differences in locomotion. White-feathered strains, however, had proportionally heavier pectoralis major (p < 0.0001), pectoralis minor (p < 0.0001), and lighter leg muscles (p < 0.0001) than brown-feathered strains. White-feathered strains and pullets in S3 also had proportionally stronger tibiae and femurs than brown-feathered strains and pullets housed in the least structurally complex system (style 1; S1) (p < 0.05). However, there were no differences found in the breaking strength of the radius and humerus between strain colours or aviary styles (p < 0.05). Therefore, strain, as well as differences in rearing aviary design, can affect the types of locomotion that growing pullets perform, which may, in turn, impact their skeletal development.

Comparison of selected indices of internal environment and condition of laying hens kept in furnished cages and in aviaries

Biochemical and hematological examination of blood and individual assessment of the birds were performed in Lohman Brown laying hens at 45 weeks of age housed in different systems. The biochemical examination revealed higher (p < .01) corticosterone levels, creatine kinase, and aspartate aminotransferase activity and lower (p < .01) levels of lactate, triglycerides, albumin, calcium, and phosphorus in aviary hens compared to hens housed in furnished cages. Hematological examination of hens housed in aviaries revealed higher (p < .05) hematocrit, leukocytes, heterophils, eosinophils, basophils, monocytes, and H/L ratio. Furthermore, hens housed in aviaries had lower (p < .01) body weight than hens in furnished cages, they were worse feathered (p < .001), had more damaged combs (p < .05), and poorer physical condition (p < .01). In contrast, caged hens showed worse (p < .01) feather condition of the wings due to abrasion and claws due to overgrowth. The results have shown that the housing system has a significant impact on the internal environment and condition of birds and that housing in aviaries without taking into account the specifics of such housing may lead to significant stress and disturbance to the welfare of laying hens.

Frequent Visits to an Outdoor Range and Lower Areas of an Aviary System Is Related to Curiosity in Commercial Free-Range Laying Hens

Individual hen preferences to spend time at particular locations within a free-range aviary system and relationships with temperament is relatively unknown. Hens (n = 769) from three commercial flocks were monitored with Radio Frequency Identification technology to determine time spent on the range, upper and lower aviary tiers, and nest boxes. Prior depopulation, novel arena (NA) and novel object (NO) tests assessed exploration and fearfulness. During early life; more time on the lower tier was associated with more lines crossed in the NA test (p < 0.05). No other evidence suggested preference during early life was related to fear or curiosity. More time on the range and lower tier were associated with heavier pre-ranging body weight and gain (p = 0.0001). Over the hens' whole life; time spent on range and lower tier was associated with approaching the NO (p < 0.01). More time spent on the upper tier was associated with less time near the NO and fewer lines crossed in NA (p < 0.01). The relationships during early and whole life use of space and some potential indicators of fearfulness were inconsistent and therefore, no strong, valid, and reliable indicators of hen fearfulness such as freezing were identified.

Pullet Rearing Affects Collisions and Perch Use in Enriched Colony Cage Layer Housing

Simple Summary

Early-life experiences for laying hens occur in the pullet rearing environment. Hens reared in aviaries use vertical space more than hens reared in non-enriched cages, but this effect has only been studied up to 23 weeks of age. Additionally, hens reared in aviaries sustain fewer keel bone fractures than those reared in non-enriched cages through the age of 73 weeks. Fractures are associated with hens having collisions with structures in their environment, but the long-term effect of rearing on collisions is not known. Lohmann LSL-Lite hens were reared in either aviaries or non-enriched cages until 19 weeks of age, then moved into enriched colony cages. Video recordings at 21, 35, and 49 weeks of age were used to identify behaviors associated with acceleration events for hens fitted with tri-axial accelerometers, as well as the proportion of birds utilizing elevated perches at two different heights. Our results indicate that hens reared in non-enriched cages experience more collisions than aviary-reared hens. Aviary-reared hens also prefer to utilize a higher perch than the cage-reared hens. These results suggest that rearing has long-term effects on space use and the ease with which hens transition among vertical spaces.

Abstract

Hens reared in aviaries (AVI) as pullets have improved spatial abilities compared to hens reared in non-enriched cages (CON). However, this effect on behavior has been shown only to 23 weeks of age. Lohmann LSL-Lite hens were reared in either CON or AVI until 19 weeks of age and then moved into enriched colony cages (ECC) containing two elevated perches of different heights (n = 6 ECC/treatment). Focal hens (3 per ECC) were fitted with tri-axial accelerometers to record acceleration events at 21, 35, and 49 weeks of age. Video recordings from each age were used to identify behaviors associated with acceleration events as well as the proportion of hens utilizing perches. CON hens experienced more acceleration events (p = 0.008) and more collisions (p = 0.04) than AVI hens during the day at 21 and 35 weeks of age. The total proportion of hens perching at night was similar between treatments across most time points, but fewer CON hens used the high perch compared to AVI hens throughout the study (p = < 0.001). Rearing in aviaries influences hen behavior out to peak lay for collisions and out to mid-lay for perch height preference in ECC.

Dust bathing in laying hens: strain, proximity to, and number of conspecifics matter

As housing laying hens in aviaries becomes more common, understanding relationships between social context and performance of key behaviors, such as dust bathing (DB), is important. Expression of behaviors may be increased or repressed by the presence of conspecifics, and degree of behavioral synchrony can affect per hen resource allocation. We investigated relationships between number of hens on litter, number of hens simultaneously DB, and interbird distances (IBD) on space used to DB and duration of DB bouts across 4 laying hen strains (Hy-Line Brown [HB], Bovan Brown [BB], DeKalb White [DW], and Hy-Line [W36]) at 28 wk of age. Brown hens needed more space to DB than white hens (HB 1125.26; BB 1146.51 vs. DW 962.65; W36 943.39 cm²; P < 0.01). More white hens occupied litter at once (43 DW, 41 W36 vs. 28 HB, 31 BB; P < 0.01), and more white hens DB simultaneously than brown hens (11 DW, 19 W36 vs. 4 HB, 4 BB; P < 0.01). Brown hens had larger average IBD (HB 13.99, BB 15.11 vs. DW 8.39, W36 7.85 cm; P < 0.01) and larger minimum IBD (HB 6.76, BB 7.35 vs. DW 1.63, W36 1.79 cm; P < 0.01) but shorter DB durations than white hens (HB 7.37, BB 9.00 vs. DW 13.91, W36 15.16 min; P < 0.01). White hens' DB area decreased if number of hens on litter increased (DW 0.85; W36 0.79 cm; P < 0.05) or minimum IBD decreased (DW 3.66, W36 2.98 cm; P < 0.01). Brown hens' DB bout duration decreased as number of hens on litter increased (HB 0.87, BB 0.95 min; P < 0.01), number of other hens DB increased (HB 0.75, BB 0.69 min; P ≤ 0.02), or minimum IBD decreased (HB 2.39, BB 2.31 min; P < 0.01). In response to smaller IBD and more hens on litter simultaneously, DW and W36 hens minimize DB area while BB and HB hens shorten DB bouts, potentially terminating bouts before fulfilling their needs. Variations in DB behavior among strains should be considered when planning and stocking laying hen aviaries.

Chlamydiosis in a Gouldian Finch (Erythrura gouldiae)

Avian chlamydiosis is an infection caused by obligate intracellular and Gram-negative bacteria belonging to the family Chlamydiaceae and has been reported in more than 450 avian species distributed in 30 orders. In particular, a high prevalence of infection has been demonstrated in wild passerine populations, including both asymptomatic and clinically ill individuals, suggesting a role of these avian species as important carriers. In May 2018, avian chlamydiosis was diagnosed in a 1-year-old male Gouldian finch (Erythrura gouldiae) at the Turlock Branch of the California Animal Health and Food Safety Laboratory System. The bird belonged to an outdoor aviary with mixed avian species, including Gouldian finches, doves (Geopelia cuneata and Spilopelia chinensis), and psittacines (Aratinga, Psittacula, Pyrrhura, and Trichoglossus sp.). Severe respiratory distress and mortality were noted among the finches. Gross and histopathologic lesions were concentrated in the liver and spleen, with a mild involvement of the upper respiratory tract. Chlamydia spp. were detected in the spleen and kidney by real-time PCR and were further confirmed by immunohistochemistry. Subsequently, Chlamydia psittaci was isolated from the liver and spleen and characterized as a CP3-like strain (genotype B). In addition, viral particles compatible with circovirus were identified in the liver by direct electron microscopy. To the authors' knowledge, this is the first report of avian chlamydiosis with hepatic viral particles consistent with circovirus infection in a Gouldian finch.

Characterising Free-Range Layer Flocks Using Unsupervised Cluster Analysis

This study aimed to identify sub-populations of free-range laying hens and describe the pattern of their resource usage, which can affect hen performance and welfare. In three commercial flocks, 3125 Lohmann Brown hens were equipped with radio-frequency identification (RFID) transponder leg bands and placed with their flock companions, resulting in a total of 40,000 hens/flock. Hens were monitored for their use of the aviary system, including feeder lines, nest boxes, and the outdoor range. K-means and agglomerative cluster analysis, optimized with the Calinski-Harabasz Criterion, was performed and identified three clusters. Individual variation in time duration was observed in all the clusters with the highest individual differences observed on the upper feeder (140 ± 1.02%) and the range (176 ± 1.03%). Hens of cluster 1 spent the least amount time on the range and the most time on the feed chain located at the upper aviary tier (p < 0.05). We conclude that an uneven load on the resources, as well as consistent and inconsistent movement patterns, occur in the hen house. Further analysis of the data sets using classification models based on support vector machines, artificial neural networks, and decision trees are warranted to investigate the contribution of these and other parameters on hen performance.

Health of Commercial Egg Laying Chickens in Different Housing Systems

To determine which type of egg-laying hen housing was best for the chickens, the workers in those housing systems, the environment, and society based on food safety and affordability, a combined research project involving egg suppliers, food manufacturers, food service representatives, and food retailers, as well as research institutions and nongovernmental organizations, was performed. This study reports the hen health and welfare portion based upon veterinary health inspections and compared mortality rates, skeletal abnormalities, causes of death determined by necropsy, and titers to infectious bronchitis and Newcastle disease viruses. Birds were housed on a preexisting Midwest layer complex, which consisted of conventional cages (CC). New houses were built adjacent to the CC house where enriched colony cages (EC) and an aviary system (AV) were installed. Two flock cycles from housing to 78 wk of age were followed. Total mortality was greatest for AV, while CC and EC birds were similar. Keel bone fractures were greatest for AV, next greatest for EC, and least for CC birds. Other skeletal abnormalities were greatest for AV birds. Birds dying from being caught in the structure, pick out, and persecution was most frequent for AV and next most frequent for EC, but nonexistent with CC birds. Infectious pododermatitis (bumblefoot) was most frequent for AV, next most frequent for EC, and essentially nonexistent for CC birds. There was little to no effect on antibody titers based upon housing type. Based upon these findings, it appears that EC housing is better for the health and welfare of egg-laying chickens than CC or AV housing.

Influence of later exposure to perches and nests on flock level distribution of hens in an aviary system during lay

Aviaries provide hens with many resources, but birds must develop motor and cognitive skills to use them properly. Introducing birds to aviaries at older ages has been reported to result in less use of perches, nests, and vertical space, which can reduce productivity and hen welfare. The objectives of this study were to examine (1) how enrichment influenced distribution of hens in the aviary during the day and (2) how enrichment influenced the distribution and roosting substrate of birds at night. Hy-Line W36 pullets were raised in floor pens before moving to laying aviaries (100 hens/aviary unit × 4 units/treatments). Control (CON) pullets were placed into aviaries at 17 wk of age (WOA). Floor (FLR) and enriched (ENR) pullets remained in floor pens until 25 WOA, and ENR birds were provided with perches and nests at 17 WOA. Birds were counted in tiers and litter areas of the aviary at morning, midday and evening at 36 and 54 WOA. Data were analyzed using generalized linear mixed models in R statistical software. At 36 WOA, ENR and CON birds occupied aviary areas at similar rates but differently from FLR birds. For example, in the morning 34% of CON hens and 30% of ENR hens occupied the highest tier compared to 15% of FLR hens (P < 0.01). At midday, 57% of CON and 57% of ENR birds were counted in litter compared with 77% of FLR birds (P < 0.01). In the evening, CON and ENR hens moved to the top tier of the aviary in greater numbers than FLR hens (22 and 17%, respectively, vs. 7%, P < 0.01). At 54 WOA, differences between FLR hens and CON/ENR hens were less pronounced, suggesting FLR hens were adapting to the aviary. Overall, we conclude that birds exposed to aviaries at 25 WOA can adapt to aviary systems, but take more time to do so than birds exposed to aviaries or vertical enrichment at 17 WOA.

Linear Space Requirements and Perch Use of Conventional Layer Hybrids and Dual-Purpose Hens in an Aviary System

Roosting on elevated perches is a behavioral priority in laying hens, which is well-investigated in both experimental and commercial settings. However, little is known about perching behavior and perch requirements of alternative hybrids, such as dual-purpose hens. The aim of the present study was to gain basic knowledge on linear space requirements and perching patterns of dual-purpose hens (Lohmann Dual, LD) by comparing them to a conventional layer line (Lohmann Brown plus, LB+). About 3,700 hens per genetic strain were housed in two consecutive batches in four compartments of an aviary system with metal perches at different heights above a grid tier. As an indicator for required perching space, the body widths of a sample of individual hens was determined by image analyses. In addition, the use of five differently located perches and one cross-brace (structural element of the aviary system) was assessed by photo-based observations during the light and the dark phase. The LD hens measured an average body width of 15.95 ± 0.08 cm, and thus occupied about 7% more linear space than the LB+ hens (14.77 ± 0.08 cm body width; P < 0.05). Overall perch use was higher during the dark compared to the light phase, both in the LB+ (3.89 ± 0.08 vs. 0.79 ± 0.03 hens/m, P < 0.05) and the LD hens (2.88 ± 0.06 vs. 0.86 ± 0.03 hens/m, P < 0.05). With a maximum of 8.17 hens/m, the LB+ hens preferred to roost on the highest perches available at night. In contrast, the LD hens also rested on the lowest perches, and showed a more even use of all perches provided. During the day, the LD hens seemed to need lower perches for easy access to the feeders, whereas more LB+ hens used the higher perches, presumably to avoid threatening conspecifics. The present results show that preferences for certain perch locations differed between conventional layers and dual-purpose hens, whereas diurnal patterns of perch use were similar in both hybrids. Therefore, perches should be designed and located in an aviary system to meet the specific preferences and behavioral needs of the hybrid housed.

Nighttime roosting substrate type and height among 4 strains of laying hens in an aviary system1

Multi-tiered aviaries for laying hens are designed to provide resources, such as perches, that allow birds to perform natural behaviors, thus improving their welfare. This research examined nighttime roosting heights and substrates used by laying hens of 4 genetic strains (Dekalb White: W1, Hy-Line W36: W2, Hy-Line Brown: B1, Bovans Brown: B2), in multitier aviaries (144 hens/unit, 4 units/strain) at 25 to 28 wk of age (peak lay). Influence of litter provision on roosting patterns of the strains was also tested. Direct observations of hens’ nighttime roosting patterns on wire floors, ledges and perches across tiers were conducted before (PRE), immediately after (IMM), and 3 wk after (ACC) hens gained access to litter. During all periods, more W1 and W2 hens roosted on middle and upper ledges than B1 and B2 hens (all P≤0.05), while more B1 and B2 hens used perches throughout the aviary than W1 and W2 hens (all P≤0.05). W1 (15±1.9, 14±3.36) and W2 (19±2.1, 18±2.6) hens occupied perches in the upper tier in greater numbers than B1 (7±3.2, 3±4.6) and B2 (11±2.1, 5±3.36) hens during PRE (P = 0.01) and ACC (P = 0.02) periods, respectively. B1 and B2 hens occupied wire floors in larger numbers than W1 and W2 hens during PRE (P = 0.02) and IMM (P = 0.03) periods, though this difference disappeared in the ACC period. During the IMM period, more W1 and W2 roosted in the lower tier, while more B1 and B2 hens were observed in the middle and upper tiers (all P ≤ 0.05). These findings demonstrate the importance of perches for B1 and B2 hens and space to roost higher in aviary units for W1 and W2 hens during the night, and underscore the need to consider aviary design, management practices, and preferences of different hen strains to ensure good hen welfare in aviaries.

Housing and Management Practices on 33 Pullet Farms in Canada

Although Canada is one of the first to provide guidelines on pullet rearing in a new Code of Practice which came into effect in March 2017, little information is available about the housing and management of pullets on Canadian farms. We surveyed 99 pullet farmers and received useable responses from 33 pullet farmers (33.3% response rate) who took part in the Start Clean-Stay Clean™ program through their provincial egg boards across Canada during October⁻December 2017 as part of a larger study. Most flocks were housed in conventional cage systems (42.4%), followed by single-tier (33.3%) and multi-tier systems (24.2%). Flocks ranged from 1⁻19 weeks of age (average: 10.5 weeks of age) and were white- (58.1%) or brown-feathered (41.9%). In general, non-cage farmers met the new requirements set out in the Code of Practice for space, perches and litter provision during pullet rearing during this transitional period. Conventional caged flocks did not have opportunities for perching and foraging, but developing new methods to provide pullets with opportunities to perch and forage will become more important as the laying hen housing system transition from conventional cages to furnished cage and non-cage housing systems in Canada progresses. Additionally, clear litter management recommendations for farmers to ensure good litter quality are needed for non-cage housing systems.

A Description of Laying Hen Husbandry and Management Practices in Canada

Simple Summary

Furnished cage and non-cage (single-tier or multi-tier) housing systems are increasingly used worldwide in efforts to improve laying hen welfare. Canadian laying hen farms are undergoing a similar transition, however, little is known about the housing and management of laying hens in these housing systems in Canada. Data collected through farmer questionnaires from 65 laying hen flocks across Canada revealed commonly used management practices in furnished cage (26), single-tier (17) and multi-tier systems (22). Non-cage systems should allow hens to perform natural behavior (e.g., foraging/dustbathing). However, a proportion of non-cage systems either did not provide litter or considered manure as a litter substrate, which could have implications for consumer perspectives on these systems. Daily flock inspections and vaccination schemes were the main practices used to maintain flock health, whereas veterinarian involvement on-farm and in the development and implementation of a flock health plan was less common. Further research is needed to make clear recommendations and to investigate how to facilitate management changes by farmers currently transitioning to furnished cage and non-cage housing systems.

Abstract

Canadian laying hen farms are transitioning from conventional cage housing to furnished cage and non-cage housing systems to improve laying hen welfare. However, little is known about the current housing and management systems in Canada. This study addresses this knowledge gap by describing different housing and management practices used on farms where laying hens were housed in furnished cages or non-cage housing systems. A questionnaire covering farm and housing conditions, litter management, nutrition and feeding, environmental control, flock characteristics, rearing and placement, health, egg production and performance were distributed through provincial egg boards to 122 producers across Canada. Data were collected from 65 laying hen flocks (52.5% response rate) in 26 furnished cage, 17 single-tier and 22 multi-tier systems. Flocks were on average 45.1 ± 14.59 weeks old (range: 19–69 weeks). Frequencies of different management practices were calculated according to housing system. Most flocks were reared in the same housing system as they were housed in during lay, with the exception of furnished cage layers which were reared in conventional cage systems. Results indicated that a large proportion of non-cage systems were either fully slatted or had manure as a litter substrate, which could have implications for consumer perspectives on these systems. Further research is needed to develop clear recommendations on proper litter management for farmers. In general, flock health was managed through daily inspections and vaccination schemes, whereas veterinarian involvement on-farm was less common. Vaccination, hygiene, and effective biosecurity should be maintained to ensure good health in laying hens in furnished cage and non-cage systems during the transition to these systems.

Nest use and patterns of egg laying and damage by 4 strains of laying hens in an aviary system

Laying hens are strongly motivated to use nests for egg laying, and alternative production systems (e.g., aviaries) provide artificial sites to meet this need and ensure efficient collection of clean, undamaged eggs. However, nests are typically not provided to allow simultaneous use by all hens; therefore, competition or mislaid eggs can result. To understand the influence of strain on laying eggs outside nests and damage to eggs, we compared daily patterns of nests use and egg laying among 4 laying hen strains (Hy-Line Brown (HB), Bovans Brown (BB), DeKalb White (DW), and Hy-Line W36 (W36)). Hens were observed over 3 consecutive days in aviaries with colony nests in the enclosure's top tier (2 nests/unit, 4 aviary units/strain, 144 hens/unit). The number and location of hens in nests and the number, location and condition of eggs throughout aviaries were recorded. Most eggs (90 to 95%) were laid in nests; however, brown hens consistently laid more non-nest eggs and damaged more eggs than white hens (P ≤ 0.05). Higher nest occupancy by brown hens was correlated with more non-nest and damaged eggs (P ≤ 0.05). In the morning, brown hens occupied more nest space and laid more nest eggs than white hens (e.g., HB vs. DW: 82.97 and 34.66% of space; 91.35 and 68.73% of nest eggs; P ≤ 0.05). At midday, white hens occupied more nest space and laid more nest eggs than brown hens (e.g., HB vs. DW: 28.47 and 15.81% of space; 27.39 and 8.29% of nest eggs; P ≤ 0.05). Brown hens preferred right nest compartments and laid more eggs there, whereas white hens preferred left compartments and W36 laid more eggs there (P ≤ 0.05). These findings indicate that different strains of hens have different patterns of nest use and laying behavior. In brown hens, heavy morning nest use was related to laying eggs outside nests and more damaged eggs, suggesting insufficient space for oviposition in nests. Specific facility design should be matched to hens’ preferences to accommodate behavioral needs of different strains.

Influence of genetic strain and access to litter on spatial distribution of 4 strains of laying hens in an aviary system

Many laying hen producers are transitioning from conventional cages to new housing systems including multi-tier aviaries. Aviary resources, such as litter areas, are intended to encourage hens’ expression of natural behaviors to improve their welfare. Little research has examined the influence of laying hen strain on distribution and behavior inside aviaries, yet differences could influence a strain's suitability for an aviary design. This research examined how laying hens of 4 strains (Hy-Line Brown [HB], Bovans Brown [BB], DeKalb White [DW], and Hy-Line W36) distributed themselves among 3 enclosed aviary tiers and 2 litter areas at peak lay (25 to 28 wk of age) and after gaining access to litter on the floor (26 wk). Observations of hens’ spatial distribution were conducted immediately before and after, and 3 wk after hens gained access to litter. More HB and BB hens were in upper tiers in morning compared to DW and W36 (all P ≤ 0.05). However, DW and W36 hens roosted in upper tiers in larger numbers than HB and BB during evening (all P ≤ 0.05). More DW and W36 hens were on litter compared to BB and HB, particularly when litter was first accessible (all P ≤ 0.05). The number of hens on litter increased over time for all strains (P ≤ 0.06). White hens on litter occupied open areas in higher numbers (P ≤ 0.05), while more brown hens occupied litter under the aviary after acclimation (P ≤ 0.05). In the dark period, W36 and DW hens were present in higher numbers in upper tiers than HB and BB, while HB and BB showed higher tier-to-tier movement than DW and W36 (P ≤ 0.05). In general, more white hens roosted higher at night and explored litter sooner, while more brown hens were near or in nests in the morning and moved at night. Distinct strain differences indicate that attention should be paid to the match between configuration of the aviary design and strain of laying hen.

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 (F_1,950 = 45.80, P < 0.001), foot pad hyperkeratosis (F_1,889 = 10.40, P = 0.001), foot pad dermatitis (F_1,792 = 20.48, P < 0.001) and bumble foot (F_1,395 = 8.52, P < 0.001) compared to pens without ramps. ISA Brown birds sustained more keel bone fractures (F_1,950 = 33.26, P < 0.001), had more foot pad hyperkeratosis (F_1,889 = 44.69, P < 0.001) and laid more floor eggs (F_1,1883 = 438.80, P < 0.001), but had fewer keel bone deviations (F_1,1473 = 6.73, P < 0.001), fewer cases of foot pad dermatitis (F_1,792 = 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.

Perch use by laying hens in a commercial aviary

Non-cage housing systems, such as the aviary, are being implemented by the laying hen industry, including in North America, in an attempt to improve the welfare of hens. Perches are a resource that is consistently included in aviaries. Hens are strongly motivated to perch, and perching can improve leg bone strength. However, hens may prefer elevated perches, particularly at night, and thus simply providing perches is not enough to improve welfare; they must be provided in a way that allows all hens to access them. Observations of laying hens using perches and ledges (flat, solid metal shelves to assist hens’ movement between tiers) in a commercial aviary revealed variation in where hens roosted within the tiered aviary enclosure across the flock cycle (peak, mid and end of lay; P < 0.001 for all age points). Hens most often preferred roosting in the highest enclosure levels, leading to crowding on upper perches and ledges while perch space remained available on lower levels. Restricted access to preferable perches may cause frustration in hens, leading to welfare issues. Hens roosted more on perches at peak lay than mid and end lay (P < 0.001) but roosted less on ledges at peak lay than mid and end lay (P < 0.001). Additionally, more hens roosted on both perches and ledges in the ‘dark’ observation period compared with the number of hens roosting during the ‘light’ observation period (P < 0.001). Further research should look at all structural elements within the system that are used by hens for roosting, such as edges of tiers and upper wire floors, to evaluate how changes in perching preferences across the lay cycle may correlate with system design and bird-based parameters.

Opinion of Belgian Egg Farmers on Hen Welfare and Its Relationship with Housing Type

Simple Summary

Until 2012, laying hens in the EU were often housed in conventional cages that offered limited space and few opportunities to perform highly motivated behaviors. Conventional cages are now banned in the EU in order to improve animal welfare. In this study, egg farmers were surveyed (winter 2013–2014) to assess whether they perceived any changes in animal welfare since changing housing systems, what role hen welfare played in choosing a new housing system, and which aspects of hen welfare they find most important. The data show that the answers differ depending on which housing system the farmers currently use and whether they had used conventional cages in the past.

Abstract

As of 2012, the EU has banned the use of conventional cages (CC) for laying hens, causing a shift in housing systems. This study’s aim was to gain insight into farmers’ opinions on hen health and welfare in their current housing systems. A survey was sent to 218 Belgian egg farmers, of which 127 (58.3%) responded, with 84 still active as egg farmer. Hen welfare tended to be less important in choosing the housing system for farmers with cage than with non-cage systems. Respondents currently using cage systems were more satisfied with hen health than respondents with non-cage systems. Reported mortality increased with farm size and was higher in furnished cages than in floor housing. Feather pecking, cannibalism, smothering and mortality were perceived to be higher in current housing systems than in CC, but only by respondents who shifted to non-cage systems from previously having had CC. Health- and production-related parameters were scored to be more important for hen welfare as compared to behavior-related parameters. Those without CC in the past rated factors relating to natural behavior to be more important for welfare than those with CC. This difference in opinion based on farmer backgrounds should be taken into account in future research.

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.

Survey of egg farmers regarding the ban on conventional cages in the EU and their opinion of alternative layer housing systems in Flanders, Belgium

On 1 January 2012, conventional cages for laying hens were banned in the European Union (EU); all egg farmers must now use alternative hen housing systems. In total, 218 Flemish egg farmers were surveyed in 2013 to 2014 regarding which housing systems they currently use, their degree of satisfaction with the system, and how they experienced the transition from conventional cages to an alternative system. The response rate was 58.3% (127 respondents). Of these, 43 (33.9%) were no longer active as an egg farmer, mainly due to the ban on conventional cages. The respondents who were active as egg farmers both before and after the transition (84, 66.1%) mainly judged the ban as negative for their own finances and for the competitive position of the Belgian egg industry, but were neutral or positive regarding the general consequences for their own business. Most respondents' hens were housed in either aviary systems (47.7%) or in alternative cage systems (38.2%). When choosing a new system, the fit into the farm and consumer demand were the most important factors. Consumer demand was the main reason for choosing a system with free-range access. In general, egg farmers were satisfied with the system they chose, although this differs between systems. When asked to compare the alternative systems to conventional cages, alternatives were judged to be better for hen welfare and consumer demand, but similar or worse for all other aspects, especially labor. Egg farmers previously using conventional cages judged alternative systems more negatively than those who had no prior experience with conventional cages. Farmers who had experience with free-range systems judged these more positively than those without this experience, e.g., for egg consumer demand, profitability, and hen welfare. These results can possibly be extrapolated to other EU countries in which conventional cages were the most common housing system until 2012, and lessons can be drawn from the farmers' experiences when implementing other animal welfare legislation that may require similar far-reaching adaptations for primary production.

Comparative evaluation of three egg production systems: Housing characteristics and management practices

This paper is an integral part of the special publication series that arose from the multidisciplinary and multi-institutional project of the Coalition for Sustainable Egg Supply (CSES). The CSES project involves 3 housing systems for egg production at the same research farm site in the Midwest, USA, namely, a conventional cage (CC) house, an aviary (AV) house, and an enriched colony (EC) house. The CC house (141.4 m L × 26.6 m W × 6.1 m H) had a nominal capacity of 200,000 hens (6 hens in a cage at a stocking density of 516 cm²/hen), and the cages were arranged in 10 rows, 8 tiers per cage row, with a perforated aisle walkway at 4-tier height. The AV house (154.2 m L × 21.3 m W × 3.0 m H) and the EC house (154.2 m L × 13.7 m W × 4.0 m H) each had a nominal capacity of 50,000 hens. The AV house had 6 rows of aviary colonies, and the EC house had 5 rows of 4-tier enriched colonies containing perches, nestbox, and scratch pads (60 hens per colony at a stocking density of 752 cm²/hen). The overarching goal of the CSES project, as stated in the opening article of this series, was to comprehensively evaluate the 3 egg production systems from the standpoints of animal behavior and well-being, environmental impact, egg safety and quality, food affordability, and worker health. So that all the area-specific papers would not have to repeat a detailed description of the production systems and the management practices, this paper is written to provide such a description and to be used as a common reference for the companion papers.

Effect of rearing environment on bone growth of pullets

Alternative housing systems for laying hens provide mechanical loading and help reduce bone loss. Moreover, achieving greater peak bone mass during pullet phase can be crucial to prevent fractures in the production period. The aim of this study was to determine the housing system effects on bone quality of pullets. Tibiae and humeri of White Leghorn pullets reared in conventional cages (CCs) and a cage-free aviary (AV) system were studied. At 16 wk, 120 birds at random from each housing system were euthanized. Right and left tibiae and humeri were collected and further analyzed. Cortical bone density and thickness were measured using computed tomography. Periosteal and endosteal dimensions were measured at the fracture site during mechanical testing. At 4, 8, 12, and 16 wk, serum concentrations of osteocalcin and hydroxylysyl pyridinoline were analyzed as markers of bone formation and resorption. Cortical bone density was higher (P<0.05) in humeri of AV pullets, and tibiae were denser (P<0.05) for AV pullets in the distal section of the bone compared to CC pullets. Ash content was higher (P<0.05) in AV humeri with no difference in tibiae ash content. Tibiae and humeri of AV pullets had a thicker cortex than the CC pullets (P<0.05). Additionally, the tibiae and humeri of AV pullets had greater (P<0.05) second moment of areas than the CC pullets. While some bone material properties between groups were different (P<0.05), the differences were so small (<7%) that they likely have no clinical significance. Serum osteocalcin concentrations were not different between the treatments, but hydroxylsyl pyridinoline concentrations were higher in CC pullets at 12 wk compared to the AV pullets and the effect reversed at 16 wk (P<0.05). These findings indicate that tibiae and humeri respond differently to load bearing activities during growth. The improved load bearing capability and stiffness in bones of AV pullets were related to increased cross-sectional geometry.

The effects of the dark house system on growth, performance and meat quality of broiler chicken

Meat production with minimum animal suffering is a humanitarian concern. Thus, the objective of this work was to observe the performance of Cobb broiler chickens from 7 to 46 days of age when raised under different installations: dark house system (DHS), conventional yellow system (CYC) and conventional blue system (CBC). The feed conversion ratio for the birds raised on the DHS was 3.8% and 2.7% lower than those for the CYC and CBC systems, respectively. Compared with the CYC and CBC systems, average daily gain under the DHS was 11.4% and 9.3% higher, respectively, and body weight at 46 days was 11.4% and 9.3% higher, respectively (P ≤ 0.05). The birds' welfare was assessed based on their stress by determining the amount of pale, soft and exudative (PSE) meat in the breast fillets. The CYC and CBC birds had 24.3% and 25.3% PSE meat, respectively, whereas the DHS birds had 37.0%. We concluded that the DHS has a greater potential to produce broiler chickens, with superior performance to conventional systems, despite the higher stress faced by the birds during the maneuvers just before slaughter.