Aviary Housing Research Articles

Making the most of life: environmental choice during rearing enhances the ability of laying hens to take opportunities.

The potential of aviary housing for improving laying hen (Gallus gallus domesticus) welfare will be constrained if rearing conditions limit the hens' behavioral ability to take opportunities. Incorporating theories on developmental plasticity and animal agency, this study aimed to determine: (1) whether a choice of litter and perch types during rearing would promote long-lasting changes in use of novel locations and resources, and (2) the influence of timing of choice provision. Laying hen chicks were assigned to either a "Single-choice" (one litter and perch type) or "Multi-choice" environment (four litter and perch types) during "Early" (day 1-week 4) and "Late" rearing (week 5-15). The environments were switched in half of the 16 pens in week 5, resulting in a 2 × 2 factorial design with four choice environment by period combinations. The allocation of perch and litter space was the same across all treatment combinations. In week 16, all groups were moved to standard aviary laying pens (Laying period, week 16-27). When first moved to the laying pens, hens with Multi-choice in either or both rearing periods were quicker to spread out in their pen than hens with Single-choice throughout rearing. Multi-choice in Early rearing also reduced the latency to use novel elevated structures (perches and nests) in the laying pens. Multi-choice during Late rearing increased success in finding and consuming hidden mealworms (tested in weeks 9-17) and increased the proportion of eggs laid on elevated nesting trays. Numerically, hens switched from Multi-choice to Single-choice in week 5 used the outdoor range less than hens switched from Single-choice to Multi-choice. These results support the hypothesis that offering multiple resource choices during rearing improves hens' ability to make the most of new opportunities by being more proactive in exploring and exploiting newly available resources. In different opportunity challenges, hens showed positive outcomes in response to choice during Early, Late or both stages of rearing, suggesting that best results can be obtained by offering environmental choice throughout rearing.

Tracking large numbers of hens in aviary housing: validation of a Radio Frequency Identification system

Tracking large numbers of hens in aviary housing: validation of a Radio Frequency Identification system

Assessing Environmental Mitigation Strategies in Controlled Cage-Free Aviary Housing Systems: Effect on Air Quality and Bioaerosols

Highlights Three mitigation strategies were tested in experimental chambers fitted as small-scale aviaries. Particle monitor and high-flow air samplers were used to sample airborne dust (PM) and bioaerosols. Oil emulsion sprinkling on the litter surface of aviaries was effective in reducing PM emissions in experimental chambers. Abstract. Alternative housing systems for laying hens are gradually replacing battery cages. Though these systems provide more space per animal and enrichments, higher concentrations of ammonia and airborne dust have been reported in those environments. In this project, three environmental control strategies and a control condition were tested in twelve experimental chambers fitted as small-scale aviaries. The experiment was conducted during three periods spanning 18 weeks, during which PM and bioaerosols were sampled in each chamber in three separate sampling campaigns. Emissions of PM, culturable bacteria and molds, total bacteria, Penicillium, and Aspergillus molds and selected fecal indicators (Campylobacter coli, Campylobacter jejuni, Clostridium perfringens, Escherichia coli, Enterococcus spp., Salmonella spp.) were assessed in each experimental chamber. Strategies that included oil emulsion sprinkling on litter surface were effective at reducing PM emissions, while no significant effect (p > 0.05) was observed on ammonia emissions, and the effect on bioaerosol was variable under the evaluated conditions. Keywords: Airborne dust, Aviaries, Bioaerosol, Laying hen alternative housing, Mitigation.

Environmental sampling methods’ influence on detection of pathogens in cage-free aviary housing

The environmental sampling of layer housing systems is essential to identifying potential pathogens that are of concern to human health. To identify the natural occurrence of pathogens (Listeria, Campylobacter, and Salmonella) at various locations in a cage-free aviary housing system, swabs were collected when hens were 22 to 39 wks of age. Duplicate environmental swabs were taken and inoculated with a low dose (101 cfu) Salmonella Enteritidis (SE) and examined for the recovery of SE from environmental samples. Detection of Listeria (P < 0.0001) and Campylobacter (P < 0.0001) varied between the environmental sample types taken: concrete dust, drag swabs, egg belt dust, manure belt scraper swabs, and wall dust. Detection of Listeria (P < 0.0001) was the highest (70.0%) at the beginning of the study (22 wk) and decreased over time. Detection of Campylobacter (P < 0.001) was also the highest at 22 wk, however the decrease over time was more gradual. Interestingly, detection of Campylobacter (P < 0.0001) was the greatest in concrete dust samples (96.25%), which can be attributed to the presence of rodent excreta in the samples. Drag swabs and manure belt scraper swabs were the best sampling types for high detection of Listeria and Campylobacter. It should be noted that Listeria recovered was not of human health concern. No naturally occurring Salmonella was identified in this study. The recovery of the SE inoculum increased over time, reaching the greatest recovery in drag (81.25%; P < 0.0001), egg belt dust (100.00%; P < 0.0001) and wall dust swabs (100.00%; P < 0.0001) by 39 wk. This high rate of SE recovery occurred just before US mandatory SE environmental monitoring at 40 to 45 wks of age. Based on this study, the use of drag and manure belt scraper swabs are effective in detecting Listeria and Campylobacter in cage-free aviary housing. Along with good pest management, the occurrence of pathogens could be monitored and reduced in laying hen flocks.

Fearfulness in aviary housed laying hens – Effects of management and potential confounding effects of the Novel Object test

Few studies have assessed fearfulness and how it relates to feather condition and management strategies in end-of-lay hens housed in commercial aviaries. As aviary housing for laying hens grows with the phasing out of cages, there is a need to ensure the currently used methods of assessing on-farm flock fearfulness are robust and to avoid confounding effects. The aim of this study was to investigate the relationship between daily management routines and plumage condition and the fearfulness of aviary housed laying hens as assessed by the Novel Object (NO) test. In addition, the study aimed at investigating potential confounding effects when performing the NO test in commercial flocks. Forty-five indoor multitiered aviary-system flocks of laying hens from across Norway were visited at the end of lay (range: 70–76 wk of age). The flocks consisted of either Lohmann LSL (n = 30) or Dekalb White (n = 15) non-beak-trimmed hens. During the visits, flock fearfulness was assessed using the NO test with 4 different objects, plumage condition was assessed using the NorWel method, and information on how the daily inspections were performed (duration and by how many different people) was collected. More hens tended to approach the NO with less damage to the breast feathers and more damage to the tail feathers in the Lohmann flocks but not in the Dekalb flocks (0.05 < P < 0.07). There was no effect of the number of people involved in the daily inspections of the hens (P = 0.56) or the amount of time spent inside the hen house per day (P = 0.80) on the number of hens approaching the NO. There was also no effect of in which corridor the NO test was carried out (wall vs inner corridors; P = 0.27). But there was an effect of the type of objects (P < 0.0001). More hens approached the “virus” NO compared to the three other objects used. The results support previous works showing a relationship between fearfulness and feather pecking and highlight the need for caution regarding hybrid differences. The results also suggest that, when performing the NO test in commercial aviaries, corridor does not have a confounding effect on this test while the type of novel object can be a confounder.

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 &lt; 0.001). The HAY group showed a reduced rate of mislaid eggs (p &lt; 0.01) and produced low egg weight and pale-yellow yolk (p &lt; 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 &lt; 0.05). However, the feather condition scores for the laying hens were similar across all treatments (p &gt; 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.

Assessing environmental control strategies in cage-free aviary housing systems: Egg production analysis and Random Forest modeling

• Three environmental control strategies were applied in experimental aviary systems. • Modelling egg production contributes insights on interactions in laying hen houses. • A Random Forest model was developed to estimate laid eggs from laying hens. • Error associated with the laid eggs’ estimation were below 0.45%. • Temperature was a key variable since gas emissions were under suggested thresholds. Since 1990, worldwide egg production has increased on average 2.8% per year. This increase has drawn the attention of animal welfare advocates. In Canada, new challenges have emerged, among them: increased awareness in animal welfare and environmental footprint and a shift to cage-free egg production systems (CFSs). Welfare assessment of environmental control strategies (ECSs), and deployment of early warning egg production systems based on on-line monitoring, have become an important field of research to understand interactions and mitigate environmental issues related to these CFSs. This study assessed the effect of selected ECSs on hen-day egg production (HDEP) and daily egg cleanliness (EGC) in experimental CFSs, using Principal Component Analysis and Linear Discriminant Analysis. The assumption that air quality conditions could play an important role in HDEP predictions was addressed by developing a machine learning method based on Random Forest models (RF) to predict HDEP daily fluctuations using measured hygrothermal and air quality conditions as input variables. A variable importance analysis further confirmed the governing variables of the egg production time series. Following that, an inquiry-driven scenario analysis was performed to identify potential changes in egg production. Results showed that the ECSs did not disrupt the egg production in the experimental CFSs. Meanwhile, A RF model with a window size of 14 days showed satisfactory performance predicting HDEP daily fluctuations with a RMSE of 0.176% and 0.368%, and a R 2 of 0.94 and 0.78, for training and testing, respectively. The temperature was the dominant governing variable among the predictors, followed by hen’s age and relative humidity. Finally, the scenario analysis revealed that a 5% temperature's increase could negatively affect the egg yield. The outcomes of this study aim to contribute to the on-line monitoring and control activities in laying hen facilities as an important aspect in Precision Livestock Farming.

Influence of forage substrates on environmental and egg microbiology in cage-free aviary housing

Within aviary systems, open litter areas are provided to allow hens to express a more robust behavioral repertoire. However, data is limited on the influence forage substrates have on environmental and egg microbiology. The objective of this study was to examine the impact of forage substrates on environmental and egg microbiology in aviary housing systems. Hens were housed in a commercial, cage-free multitier aviary with open litter areas, which contained one of three forage substrates (straw, artificial turf, and shavings) or bare concrete floors. Environmental and egg sampling occurred at hen ages: 25, 37, 51, and 64 wk. Drag swab aerobic bacteria levels from the litter area of the artificial turf group were lower (6.86 log cfu/mL) compared to the other substrate groups ( P < 0.001; concrete: 7.39 log cfu/mL; straw: 7.40 log cfu/mL; shavings: 7.16 log cfu/mL) as the flocks aged. As the flocks aged, lower levels of yeasts and molds were observed in the litter area of the artificial turf group (6.72 log cfu/mL) compared to the other substrates ( P < 0.02; concrete: 7.54 log cfu/mL; straw: 7.36 log cfu/mL; shavings: 7.61 log cfu/mL). No differences in Salmonella, Campylobacter , and Listeria spp. prevalence were observed between the substrate groups. Although aerobic bacteria, Enterobacteriaceae , yeasts and molds, and pathogens were present in the environment of the substrate groups, it did not impact egg microbiology. The lower microbial and yeasts and molds levels in this study suggest that artificial turf could be an appropriate forage substrate for commercial cage-free aviary housing, however further research is needed.

봄철 산란계사 사육형태별 미세먼지 및 암모니아 농도 비교

This study was conducted to determine the concentrations of particulate matter (PM) and NH3 emissions from different types of laying hens poultry houses during spring. The concentrations of PM and NH3 were measured three times (2-week intervals; March to May) in Floor-pen-, Aviary-, and Cage-type poultry houses. Overall, PM₁₀ and PM_2.5 concentrations were found to be low from 22:00 to 04:00. The PM₁₀ and PM_2.5 concentrations in Floor-pen and Cage houses were similar with no significant daily deviation. NH₃ concentrations measured over 24 h at the center and end of Floor-pen house were relatively constant. Irrespective of measurement location, NH₃ concentrations were the lowest in Floor-pen house. Moreover, NH₃ concentrations were higher at the end of Floor-pen and Aviary houses than that at the center; however, lower concentrations of NH₃ were detected at the end of Cage house. The concentrations of PM₁₀ and PM_2.5 around the poultry houses were 57.5 and 34.0 μg/m³, respectively, with the daily average PM₁₀ and PM_2.5 concentrations (4,730 and 447.7 μg/m³, respective) being the highest in Aviary house. The concentrations of NH₃ at the center and end of Cage house were the highest at 12.0 and 9.31 ppm, respectively. Furthermore, in Cage house, the emission factor of NH₃ was the lowest, whereas there was no significant difference on that of NH₃. In conclusion, among the three types of poultry houses assessed, PM (PM₁₀, PM_2.5) concentrations were higher in Aviary house, whereas NH3 concentrations were higher in Cage house.

동절기 산란계사 사육형태별 배출되는 미세먼지 및 암모니아 농도

In this study, we measured the concentration of particulate matter (PM) and ammonia (NH₃) emission in the winters according to the breeding type of laying hen houses. Measurements were performed thrice in Barn, Aviary, and Cage houses every 2 weeks from December to January. The changes in the PM₁₀ and PM_2.5 concentrations were similar in all three breeding types. The PM₁₀ and PM_2.5 concentrations, measured three times, were the highest in the Aviary house. In the results measured by time, the PM₁₀ and PM_2.5 concentrations were the lowest during the dark period (22:00 to 4:00) of the day. The NH₃ concentration was the highest in the Cage house and the lowest in the Barn house. Regarding emissions over time, the results of the three measurements showed different patterns and differed from those of the PM. In addition, with passage of time from the 1st (december) to 3rd (january), the NH₃ concentration gradually increased. The daily PM₁₀ and PM_2.5 concentrations in the Aviary house, which were higher than those of the other houses, were 4,787 μg/m³ and 388.6 μg/m³, respectively, while, the PM₁₀ and PM_2.5 concentrations outside the poultry houses were 226.0 μg/m³ and 39.3 μg/m³, respectively. The daily NH₃ concentration was 7.70 ppm and 9.20 ppm at the center and end of the Cage house, respectively. This was higher than that in the other houses. In conclusion, the concentrations of PM (PM₁₀, PM_2.5) and NH₃ were the highest in the Aviary and Cage laying hen houses, respectively.

Utjecaj sustava držanja na fizikalna, morfološka i mehanička svojstva jaja japanskih prepelica

The objective of this study was to determine the influence of housing system on the physical, morphological, and mechanical properties of Japanese quail (Coturnix coturnix japonica) eggs. A total of 240 eggs were collected from Japanese quails kept in two different housing systems: cage housing and aviary housing system (120 eggs from each housing system). Eggs from cage housing system were significantly (P<0.05) heavier than eggs from aviary housing system (11.85 g vs. 10.93 g), and were also longer, wider and had significantly (P<0.05) larger geometric mean diameter, surface area and volume. No statistically significant difference in albumen and yolk content was observed between eggs from cage and aviary housing system. Eggs from aviary housing system had significantly higher shell content and shell strength and required greater force to eggshell breaking. The average force required to breaking the shell of Japanese quail eggs from cage and aviary housing system in all three axes was 14.36 N and 12.70 N, respectively.

Incidence and associated risk factors of necrotic enteritis in Belgian layer pullet flocks

ABSTRACT Necrotic enteritis (NE) caused by Clostridium perfringens is commonly reported in broilers. Recently, increased NE prevalence in layer breeds was reported in the Indian subcontinent. NE is also frequently observed by veterinary practitioners in Europe, mainly during the pullet rearing phase. In this study, data from layer pullet flocks in Belgium over a 5-year period (2013–2017) were used to assess the incidence of NE and identify potential risk factors for NE in layer pullets. NE was observed in 26% of the layer pullet flocks receiving veterinary intervention. This accounts for an overall estimated NE incidence of 12.3% in Belgian layer pullet flocks. Occurrence of NE was significantly associated with coccidiosis, with flocks being diagnosed with coccidiosis being two-fold more likely to develop NE. Additionally, birds kept in aviary houses were less prone to NE than flocks reared in floor systems or enriched cages. At necropsy, necrotic lesions in the small intestine were comparable to NE in broilers. A single strain of C. perfringens was isolated from the necrotic lesions of three different birds from the same flock; however, no NetB could be detected.

Concentration and size distribution of particulate matter in a new aviary system for laying hens in China

ABSTRACTParticulate matter (PM) from poultry production facilities may strongly affect the health of animals and workers in the houses, and PM emitted to the ambient air is an important pollution source to the surrounding areas. Aviary system is considered as a welfare friendly production system for laying hens. However, its air quality is typically worse as compared with conventional cage systems, because of the higher PM concentration of indoor air and other airborne contaminants. Furthermore, PM’s physical property, which has a direct impact on the penetration depth into the lungs of the birds and humans, is largely unknown for the aviary system. Therefore, a systematic method was utilized to investigate the characteristics of particles in the aviary house with large cage aviary unit system (LCAU) in Beijing, China. For the field measurements, three measuring locations were selected with two inside and one outside the house with LCAU to continuously monitor PM concentrations and collect the samples for particle size distribution (PSD) analysis. Results showed that PM2.5, PM10, and total suspended particulate (TSP) concentrations averaged at 0.037 ± 0.025 mg/m3, 0.42 ± 0.10 mg/m3, and 1.92 ± 1.91 mg/m3, respectively. Particle concentrations increased from October to December due to less ventilation as the weather got colder, and were generally affected by stocking density, ventilation rate, birds’ activities, and housing system. Meanwhile, indoor PM2.5 concentration was easily impacted by the ambient air quality. Mass median diameter (MMD) and mass geometric standard deviation (MGSD) of the TSP during the measurement were 18.92 ± 7.08 μm and 3.11 ± 0.31, respectively. Count median diameter (CMD) and count geometric standard deviation (CGSD) were 1.94 ± 0.14 μm and 1.48 ± 0.08, respectively. Results indicated that the aviary system can attain a good indoor condition by suitable system design and environment control strategy.Implications: Indoor PM2.5 concentration of the layer house can be significantly affected by ambient air quality when the air quality index (AQI) was larger than 100. PM2.5 and PM10 concentrations of the layer house with a LCAU system were comparable to the cage system. TSP concentration was higher, and PM size was larger than most of the cage system. System design, larger space volume, and higher ventilation rate were the main influence factors. Good indoor environment of the aviary system can be achieved through the reasonable design of the production system and appropriate environment control strategy.

MORPHOMETRIC AND REPRODUCTIVE CHARACTERISTICS OF THE CENTRAL ASIAN SHEPHERD DOG BREED UNDER DIFFERENT HOUSING CONDITIONS

The article reflects the results of the studies on the Central Asian Shepherd dog breed. The dog assessment data on the main measurements, body indices, and certain characteristics of reproduction in various housing systems are considered. The objects of the research were adult dogs of the Central Asian Shepherd breed born in 2012 - 2017, 51 heads were kept by amateurs in Kherson city. It was established that only 39.22 % of the total number was kept under apartment conditions, while the owners preferred males - their specific weight was from 58.06 % to 75 % of the total number. The vast majority (87.50 %) of the dogs, regardless of the conditions of housing, were never used in reproduction. The intensity of the use of the female dogs was associated with the conditions of housing – under of the aviary housing, at least once in their life they received offspring of 46.15 % of female dogs, under apartment housing – only 16.67 %. The average number of healthy puppies in the offspring was 8.29 heads. The speed of realization of the puppies was influenced by their gender. At the age of 4 to 8 weeks, 63.79 % of the young animals were sold, of which 73.33 % were males and only 53.57 % were females. Regardless of the system of dog housing, pronounced sexual dimorphism was observed by the measurements (3.98 - 8.78 cm). Relative to the minimum size, the female dogs had an advantage at the level of 11.86 %, males - at 10.46 %. Thus, the female dogs were relatively larger than the males. The apartment housing did not affect the size of the dogs negatively. For most measurements, the advantage of the apartment kept dogs ranged from 2.09 to 5.54 %. The live weight variability was greater than the measurements (variation coefficients ranged between 6.82 - 10.21 %), sexual dimorphism was quite pronounced – the males were 5.98 - 6.21 % heavier than the female dogs. As in the measurements, the female dogs had higher rates exceeding the minimum requirements for standard live weight than the males (31.75 % and 17.59 %). The apartment kept dogs had an advantage in live weight compared to the aviary kept dogs from 4.70 % to 5.73 %. All dogs under study had a moderately stretched format, the value of the format index ranged from 102.67 to 106.44 units with the severity of sexual dimorphism at the level of 1.58 - 1.91 %. The aviary kept dogs had a longer format, the excess was from 1.74 % (female dogs) to 2.08 % (males), they had a lower density index than the dogs of the apartment housing (difference of 3.09 - 3.39 %). According to the mass index, there were no significant differences between the dogs, which were kept by the compared systems.

Hen housing system information effects on U.S. egg demand

The U.S. egg industry has been moving rapidly towards “cage-free” aviary housing as an alternative to conventional cages for hens. A choice experiment was used to evaluate the U.S. public’s willingness to pay (WTP) for egg attributes including housing system, color, size, and certifying agency. A significant difference in WTP for hen housing systems was found using video information treatments describing hen housing systems. When respondents were shown videos of egg production systems, they were indifferent between cage-free aviary and the alternative enriched colony hen housing system whereas with no video information the respondents clearly preferred the cage-free system. Results point towards potential public misunderstanding of the costs and benefits associated with the “cage-free” egg label designation and highlight potential discrepancies between industry commitments and informed consumer preferences.

Physical and mechanical characteristics of Hisex Brown hen eggs from three different housing systems

The aim of this study was to compare physical and mechanical characteristics of Hisex hen eggs collected from three different housing systems: enriched cage housing, aviary housing, and free-range systems. The following physical and mechanical characteristics if eggs were compared: dimensions, surface area, volume, sphericity, shape index, shell thickness, weight, composition, yolk to albumen ratio, rupture force, specific deformation, absorbed energy, and firmness. The largest and heaviest eggs were collected from cage housing, followed by eggs from free-range systems and aviary housing. According to shape index, eggs from aviary housing can be described as round, while eggs from cage housing and free-range systems can be characterised as normal or standard. Eggs from free-range laying hens had the highest yolk percentage and yolk to albumen ratio (26.2% and 0.427). In comparison to eggs from aviary housing and free-range systems, eggs from enriched cage housing had the thickest shells and the highest shell strength, and required the highest force to rupture those eggs. The average force required to rupture Hisex Brown hen eggs from cage housing in all three axes was 44.14 N, which was 12.1% higher than the average force required to rupture eggs from a free-range system (39.37 N) and 17.1% higher than the average force required to rupture eggs from aviary housing (37.68 N). The highest forces required to rupture eggs from all three housing systems were determined on loading along the X-front axis and the lowest forces were determined along the Z-axis. The results obtained in this study can be useful to producers when selecting hen housing systems in order to reduce egg damage during storage and transport. Keywords: egg composition, egg weight, rupture force, shape index, shell thickness

Improved methods for reducing translocation mortality and obtaining reliable population projections for reintroduction of the New Zealand Rifleman Acanthisitta chloris

SummaryDespite many notable successes, the failure rate of animal translocations remains high. Conservation practitioners and reintroduction specialists have emphasised the need for ongoing documentation of translocation attempts, whether successful or not, including detailed methodologies and monitoring approaches. This study reports on the first translocation of the North Island subspecies of New Zealand’s smallest bird, the endemic Rifleman Acanthisitta chloris granti. We describe an improved transfer methodology following recommendations arising from a previous translocation of South Island Rifleman Acanthisitta chloris chloris. Key modifications included a reduced capture window, shorter holding times, lack of extended aviary housing, and separation of territorial individuals during holding. Survival from capture to release increased from 52% to 97% using this new methodology. However, only 22% of 83 released birds were found in the reserve the next breeding season, resulting in an initial breeding population of only six males and five females. An integrated Bayesian analysis of three years of subsequent population data, including a population boost from a second translocation, projected a median decrease to 0–5 females over 10 years, but with 95% prediction intervals ranging from 0 to 33. These projections explicitly account for parameter uncertainty, as well as demographic stochasticity, and illustrate the need to do so when making inferences for small reintroduced populations.

Effects of litter floor access and inclusion of experienced hens in aviary housing on floor eggs, litter condition, air quality, and hen welfare

ABSTRACTWith different cage-free (CF) housing styles and management schemes, retailers have developed their own CF criteria. One highly debated aspect is if hens may be kept inside the system for part of the day—during the first few hours after lights-on. Research is lacking regarding the impacts of such a practice on hen welfare, incidence of eggs laid on the litter floor, litter condition, and air quality. This 14-mo field study was conducted to help assess such impacts. Hens (Dekalb White) in an aviary house (50,000-hen nominal capacity) were allowed to have full litter access (FLA) vs. part-time litter access (PLA) from 10:50 am to 9:00 pm, coupled with the absence or presence of experienced hens (1.5% of the population), hence a 2 × 2 factorial arrangement. The measured variables included a) incidence of floor eggs, b) percentage of birds remaining on litter floor at night, c) mortality, d) body weight (BW) and BW uniformity, e) litter condition (depth, moisture content, texture, amount removed, and bacteria concentration), f) environmental conditions, and g) welfare conditions (10 variables). Compared to FLA, PLA had a significantly lower incidence of floor eggs (1.4 ± 0.1 vs. 12.6 ± 1.1 eggs per hen housed as of 76 weeks of age (WOA), i.e., approximately 89% reduction), less manure deposition on the floor (0.53 ± 0.02 vs. 1.05 ± 0.04 kg/100 hens/d, dry basis, i.e., approximately 50% reduction), and lower ammonia concentrations due to drier litter (averaging 22% lower). Inclusion of 1.5% experienced hens in the young flock did not show benefit of reducing the incidence of floor eggs (P = 0.48). The percentage of hens remaining on the floor at night was low (< 0.01%) in all cases from 24 WOA onward. No differences were detected between FLA and PLA in hen welfare conditions, mortality, BW, BW uniformity, bacteria concentration in the litter, air temperature, or relative humidity.

Hen genetic strain and extended cold storage influence on physical egg quality from cage-free aviary housing system

In the United States, there is an increase in need for cage-free eggs in retail and food manufacturing sectors. Understanding the impact of cage-free systems and the corresponding management on egg quality is pertinent as the U.S. industry adapts existing housing and builds new cage-free housing structures. A study was conducted comparing 2 brown shell and 2 white shell hen strains housed in a cage-free aviary system. Each set of eggs were placed in cold storage and assessed at 0, 2, 4, 8, and 12 wk. Eggs were collected at 21, 31, 42, and 60 wk of hen age. A full profile of physical quality measurements was conducted on up to 18 intact eggs for each hen strain/egg storage/hen age combination. Egg weight increased approximately 10g for brown shell and 14g for white shell eggs as hens aged. Many of the properties monitored were significantly impacted by all 3 main effects (hen strain, egg storage, and hen age) resulting in 3-way interactions. A brown and a white shell strain had stronger shells (44N; P <0.0001) than the remaining brown and white shell strains (42N and 39N, respectively). The current study also determined volume of shell, total length, maximum width, and percent length at maximum width to more accurately indicate egg shape than shape index. One brown shell strain produced eggs with the most consistent shape characteristics over the hen ages monitored. White shell eggs from the cage-free aviary housing produced the highest whole-egg total solids between 31 to 60 wk of hen age, whereas brown shell eggs resulted in the most consistent level of whole-egg total solids (22-23.5%). The brown and white shell strains in the current study produce cage-free aviary eggs with distinctive physical quality attributes. The outcomes from this study can be utilized by the U.S. egg industry in planning management strategies and market placement of cage-free eggs.

Influence of physical activity on tibial bone material properties in laying hens

Laying hens develop a type of osteoporosis that arises from a loss of structural bone, resulting in high incidence of fractures. In this study, a comparison of bone material properties was made for lines of hens created by divergent selection to have high and low bone strength and housed in either individual cages, with restricted mobility, or in an aviary system, with opportunity for increased mobility. Improvement of bone biomechanics in the high line hens and in aviary housing was mainly due to increased bone mass, thicker cortical bone and more medullary bone. However, bone material properties such as cortical and medullary bone mineral composition and crystallinity as well as collagen maturity did not differ between lines. However, bone material properties of birds from the different type of housing were markedly different. The cortical bone in aviary birds had a lower degree of mineralization and bone mineral was less mature and less organized than in caged birds. These differences can be explained by increased bone turnover rates due to the higher physical activity of aviary birds that stimulates bone formation and bone remodeling. Multivariate statistical analyses shows that both cortical and medullary bone contribute to breaking strengthThe cortical thickness was the single most important contributor while its degree of mineralization and porosity had a smaller contribution. Bone properties had poorer correlations with mechanical properties in cage birds than in aviary birds presumably due to the greater number of structural defects of cortical bone in cage birds.