Individual Hens Research Articles

Later exposure to perches and nests reduces individual hens' occupancy of vertical space in an aviary and increases force of falls at night

Tiered aviaries are intended to improve laying hen welfare by providing resources that enable them to perform essential behaviors. However, hens must be able to navigate these complex systems efficiently and safely. This study investigated the influence of providing perches and nests starting at 17 or 25 wk of age (WOA) on hens' use of vertical space in an aviary at 36 and 54 WOA. Three treatments were applied to pullets raised in floor pens until 17 WOA (4 units/treatment; 100 hens/unit). Control (CON) pullets were placed into aviaries at 17 WOA. Floor (FLR) pullets were placed into aviaries at 25 WOA. Perches and nests were placed in enriched (ENR) pullets' floor pens at 17 WOA prior to moving ENR birds to aviaries at 25 WOA. Five focal hens/unit (n = 20 total hens/treatment) were fitted with accelerometers, and their diurnal movement (g) and frequency (n) and acceleration (g) of falls at night were recorded. Direct observation of focal hens was conducted for 6 min/hen at morning, midday, and evening for 3 consecutive days at 36 and 54 WOA, and location and time spent on vertical tiers were recorded. At 36 WOA, FLR hens spent more time on litter than CON and ENR, which spent more time in the top tier (all P ≤ 0.05). ENR hens exhibited higher vertical movement than CON and FLR hens (0.8, 0.6, and 0.3 g; P = 0.003). CON hens fell most often at night (16 vs. 9 FLR and 5 ENR), whereas FLR hens had higher acceleration and calculated collision force than CON and ENR hens during falls (0.8, 0.5, 0.3 g and 15, 10, 5 N, respectively; P ≤ 0.05). At 54 WOA, hens' movement and vertical distribution were similar across treatments. Delaying birds' access to perches and nests until 25 WOA impacted their movement, vertical space use, and falls at night for at least 10 wk. However, providing perches and nests at 17 WOA, even in floor pens, considerably mitigated such impacts.

Application of open field, tonic immobility, and attention bias tests to hens with different ranging patterns.

Assessment of negative affective states is a key component of animal welfare research. In laying hens, excessive fearfulness results in reduced production and increased sensitivity to stress. Fearfulness can be defined as a response to a known threat, but anxiety is a response to an unknown threat and may have similar negative consequences. The open field test and tonic immobility test are commonly applied to measure fearfulness in laying hens. An attention bias test that measured individual hen’s responses to playback of a conspecific alarm call in the presence of food was recently pharmacologically validated using an anxiogenic drug but was confounded by the hen’s typical motionless response in a novel environment. The current study used 56-week old free-range layers to further assess the validity of an attention bias test to differentiate ranging treatment groups in comparison with the open field and tonic immobility tests. The selected hens varied in their range use patterns as tracked by radio-frequency identification technology. ‘Indoor’ hens did not access the range and ‘outdoor’ hens ranged daily; previous research has confirmed higher fearfulness in hens that remain indoors. The tonic immobility test did not differentiate ranging groups (P = 0.34), but indoor birds were slower to first step (P = 0.03) and stepped less (P = 0.02) in the open field test. The attention bias test occurred in an isolated wooden box using a conspecific alarm call playback (a threat) and mixed grain (a positive stimulus). The behavioural response of latency to resume eating following playback of the alarm call was measured to differentiate the anxiety states of the indoor and outdoor ranging birds. Before the attention bias test could occur, birds had to be habituated to the test box across three separate 5-minute sessions to increase the willingness to feed within the novel test environment. All birds ate faster across time (P < 0.001) but the indoor birds were slower to eat than the outdoor birds (P < 0.001). In this study, the latency to resume eating following an alarm call was determined to be a poor measure for highly anxious birds as they failed to eat at all. Forty-six percent of indoor hens were excluded for not eating across the 5-minute test. Of the birds that did eat, only 7% of indoor hens ate following playback of the alarm call, compared with 36% of outdoor hens. This repetition of an attention bias test for laying hens highlights the challenges in assessing hens with extreme fearful/anxious responses and that information may be missed when non-performing hens are excluded from behavioural tests. We suggest that latency to eat in a novel arena without any alarm call playback is an informative measure of anxious state that can be applied to all hens but consideration must be made of potential differences in food motivation.

Keel impacts and associated behaviors in laying hens

Factors contributing to the development of keel bone damage are not well understood. This study aimed to identify behaviors and cage structures associated with acceleration events experienced by individual hens at their keels as the birds navigated their enriched colony cage environments. Additionally, we aimed to characterize the accelerations associated with these behaviors, as we postulated that behaviors associated with higher accelerations may be more likely to lead to keel bone damage. Sixty five 19 week old Hyline W36 hens were placed in each of 12 enriched colony cages. Ten focal hens per cage were selected for observation. Each hen was fitted with a jacket which contained a tri-axial accelerometer with an external sensor that was fitted into a small pocked over the hen’s keel. The logger recorded any time that the hen sustained an acceleration event at the keel (>12 G-units). Logger output was matched with video data, allowing us to describe the behavior of the affected bird at the time of the acceleration event recorded at the keel. Data on each bird were collected continuously over two 3-week periods, when the hens were between 52–60 and 74–83 weeks of age. Collisions accounted for nearly 81% of observed acceleration events with acceleration peaks of at least 20 G-units. The majority of collisions were with the perch and were sustained mainly as the hen attempted to ascend onto it. It has previously been reported that the prevalence of keel bone fractures is higher among hens housed in cages that do versus do not contain perches. This study lends support to the growing body of evidence indicating that interactions with perch contribute to the keel bone damage sustained by laying hens housed in enriched colony cage systems, however, the relationship between acceleration events and occurrence of keel bone damage has yet to be directly assessed.

The intake pattern and feed preference of layer hens selected for high or low feed conversion ratio.

Feed accounts for the greatest proportion of egg production costs and there is substantial variation in feed to egg conversion ratio (FCR) efficiency between individual hens. Despite this understanding, there is a paucity of information regarding layer hen feeding behaviour, diet selection and its impact on feed efficiency. It was hypothesised that variation in feed to egg conversion efficiency between hens may be influenced by feeding behaviour. For this experiment, two 35-bird groups of ISA Brown layers were selected from 450 individually caged hens at 25–30 weeks of age for either low FCR < 1.8 ± 0.02 (high feed efficiency (HFE) or high FCR > 2.1 ± 0.02 (low feed efficiency (LFE)). For each of these 70 hens, intake of an ad-libitum mash diet at 2-minute time intervals, 24 h a day, for 7 days was determined alongside behavioural assessment and estimation of the selection of components of the mash. The group selected for HFE had a lower feed intake, similar egg mass and associated lower FCR when compared with the LFE group. Whilst feed intake patterns were similar between HFE and LFE hens, there was a distinct intake pattern for all layer hens with intake rate increasing from 0300 to 1700 h with a sharp decline to 2200 h. High feed efficiency hens selected a diet with 25% more ash and 4% less gross energy than LFE hens. The LFE hens also spent more time eating with more walking events, but less time spent resting, drinking, preening and cage pecking events as compared with HFE hens. In summary, there was no contrasting diurnal pattern of feed consumption behaviour between the groups ranked on feed efficiency, however high feed efficiency hens consumed less feed and selected a diet with greater ash content and lower gross energy as compared with LFE hens. Our work is now focused on individual hen diet selection from mash diets with an aim of formulating precision, targeted diets for greater feed efficiency.

Transfer of natural auto-antibodies via egg yolk in chickens divergently selected for natural antibodies binding keyhole limpet hemocyanin

Barcodes of natural auto-antibody (NAAb) profiles based on staining intensity of isotypes binding numbers of self-(tissue) antigen fragments were suggested as parameters for immune diversity, and related to genetic background and health status in man, rodents and poultry. Here, hens, eggs and hatchlings from chicken lines divergently selected and bred for high (H line) or low (L line) total natural antibodies (NAb) levels in plasma binding keyhole limpet hemocyanin (KLH) at 16 weeks of age were tested for their NAAb repertoire binding chicken liver homogenate (CLH) fragments using quantitative Western immunoblotting. The aims of this study were 1. to detect line differences between the H and L line adult hens, eggs and hatchlings for the IgM and IgG isotypes binding CLH fragments, 2. study the presence of NAAb of both isotypes in yolk and albumen, as well as in hatchlings to detect a maternal NAAb transfer route via the egg to the hatchling, and 3. study whether new self-antigen binding isotypes and idiotypes are present in the hatchling.NAAb binding CLH fragments were found in plasma of adult hens (both IgM and IgG), in yolk (IgG only), and hatchlings (mostly IgG, but low levels of IgM). Auto-profiles of IgM showed homogeneity, while IgG profiles were heterogenic between individual hens and individual hatchlings. Significant higher levels as indicated by staining intensity and number of stained CLH fragments were found in plasma of hens genetically selected for high levels of NAb binding KLH. Lines could be clustered based on their auto-profiles indicating that profiles of self-binding IgM and IgG antibodies are genetically based. Visual comparison, clustering and correlation of hens and their hatchlings showed similarities for the IgG, but not the IgM isotype, indicating maternal transfer of IgG NAAb via the yolk. The IgM profile in the hatchlings on the other hand might represent neonatal self-binding antibody formation. As a consequence, hatchlings initially depend for self-binding antibodies on maternal IgG provision during early life.

An attention bias test to assess anxiety states in laying hens.

Fear is a response to a known threat, anxiety is a response to a perceived threat. Both of these affective states can be detrimental to animal welfare in modern housing environments. In comparison to the well-validated tests for assessing fear in laying hens, tests for measuring anxiety are less developed. Perception of a threat can result in an attention bias that may indicate anxious affective states in individual hens following playback of an alarm call. In Experiment 1, an attention bias test was applied to hens that differed in their range access to show that hens that never ranged were more vigilant (stretching of the neck and looking around: P < 0.001) and slower to feed following the second alarm call playback (P = 0.01) compared with hens that ranged daily. All hens showed a reduction in comb temperature following the first alarm call (P < 0.001). In Experiment 2, an open field test was used to determine an effective dose of 2 mg/kg for the anxiogenic drug meta-Chlorophenylpiperazine (m-CPP) in adult laying hens. Hens dosed with 2 mg/kg showed reduced locomotion compared with a saline solution (P < 0.05). In Experiment 3, 2 mg/kg m-CPP or saline was administered to adult hens previously habituated to the open field arena to pharmacologically validate an attention bias test as a measure of anxiety. Hens dosed with m-CPP were slower to feed (P = 0.02) and faster to vocalize following a second alarm call playback (P = 0.03) but these hens did not exhibit the same vigilance behavior as documented in Experiment 1. The m-CPP hens also spent more time stepping and vocalizing (both P < 0.001) than the saline hens. An attention bias test could be used to assess anxiety. However, behavioral responses of hens may vary depending on their age or test environment familiarity, thus further refinement of the test is required. In these tests, 2 mg/kg of m-CPP resulted in motionless behavior when the environment was novel, but more movement and vocalizing when the environment was familiar. The extreme behavioral phenotypes exhibited by individually-tested birds may both be indicators of negative states.

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.

Establishment of Hy-Line commercial laying hen whole blood gas and biochemistry reference intervals utilizing portable i-STAT1 clinical analyzer

Blood gas and biochemistry reference intervals were established for 3 genetically distinct commercial varieties (CVs) of Hy-Line laying hens: 2 brown-egg layers (Hy-Line Brown, Hy-Line Silver Brown) and a tint-egg layer (Hy-Line Sonia) utilizing the i-STAT1 analyzer. Each respective variety of laying hen was sampled on a replicate cycle of 2 wk for a total of 6 replicates (35 to 46 wk of age). Blood samples were obtained in the production house from the brachial vein, and subsequently analyzed by the i-STAT1 portable device. i-STAT1 clinical analyzer reports blood gas and biochemistry values for the following parameters: pH, partial pressure of carbon dioxide (pvCO2, mm Hg), partial pressure of oxygen (pvO2, mm Hg), bicarbonate (HCO3, mmol/L), base excess (BE, mmol/L), saturation of oxygen on hemoglobin (sO2%), glucose (Glu, mg/dL), sodium (Na, mmol/L), potassium (K, mmol/L), total concentration of carbon dioxide (TCO2, mmol/L), ionized calcium (iCa, mmol/L), hematocrit (Hct % packed cell volume [PCV]), hemoglobin (Hb, g/dL). A total of 1,800 individual hen i-STAT1 records were utilized in the establishment of reference interval values for the 13 parameters between the 3 CVs. Statistical analysis via ANOVA and Tukey's test revealed significant line differences for all 13 blood gas and chemistry parameters measured, with particularly interesting results in iCa. The blood gas and chemistry parameters collected in this study will serve as reference intervals to set the framework for potential future correlations to genetic markers, physiological abnormalities, and production performance.

Keel bone fractures are associated with individual mobility of laying hens in an aviary system

Keel bone fractures (KBF) in laying hens have been shown to cause pain and impair mobility under experimental conditions. However, it is not known how KBF relates to the mobility of individual hens housed in aviary systems. For the current study, 120 focal hens (60 Lohmann Brown (LB) and 60 Lohmann Selected Leghorn (LSL)) were kept in six identical pens equipped with a commercially relevant aviary system (20 LSL focal hens + 205 LB or 20 LB focal hens + 205 LSL per pen, respectively). Data on hen mobility were recorded at 21, 24, 27, 31, 35, 39, 44, 48, 52, 57 and 61 weeks of age. Infrared receivers were attached to the legs of focal hens. They recorded zone-specific codes between five zones (litter, lower tier, nest boxes, top tier, and wintergarden) at a frequency of 1 Hz for six consecutive days per week of age. At the end of each data collection period, hens were radiographed to assess keel bone fracture severity. Data were analysed using (generalized) linear mixed effect models. With increasing KBF severity, LB hens spent more time in the top tier (p = 0.005) and less time in the litter zone (p < 0.0001) and in the lower tier (p = 0.001). Independent of KBF, LB hens spent less time in the wintergarden (p = 0.011) and in the lower tier (p = 0.002) and more time in the top tier (p = 0.009) with increasing age. The likelihood of crossing more than one zone within a movement (e.g., jumping from the top tier to the litter directly) increased with increasing KBF severity (p = 0.036). Lohmann Selected Leghorn hens spent most time in the nest box zone and top tier and had few transitions between zones. With increasing age, LSL hens spent less time in the nest box zone (p = 0.018) and more time in the top tier (p = 0.006). Irrespective of strain, hens crossed fewer zones with increasing age (LB: p = 0.009, LSL: p = 0.002). Our findings indicate that hens having KBF prioritized paths among the upper tiers (i.e., mostly between nest box zone and top tier) over paths among the mid and lower tiers (i.e., between litter, lower tier and nest box zone). We conclude that behavioural adaptation to pain, the accessibility of resources as well as social factors might be important mechanisms driving individual mobility in response to KBF.

Modeling egg production as a means of optimizing dietary nutrient contents for laying hens.

Poultry geneticists have been highly successful in improving the egg output and feed efficiency of laying hens and, to a lesser extent, broiler breeders. As the potential output of these birds has changed so have their nutrient requirements and these are reflected in user manual guidelines, tables of requirements, and company know-how. However, the basis of these suggested changes is unlikely to be based on theoretical calculations of the updated requirements of the bird due to the lack of a robust theory describing the manner in which the nutrient requirements are calculated. Such a theory has been developed recently and is described in this article. To calculate the amino acid and energy requirements of an individual laying hen, it is necessary to be able to predict its potential body protein weight at the start of lay and its potential egg output and egg weight over time (Emmans and Fisher, 1986). From this information, and the nutritional constants that describe the rates of conversion of feed nutrients to maintenance and egg nutrients, it is possible to calculate the daily requirement of each of the amino acids and energy throughout the laying period. Once the requirements for an individual hen are correctly calculated, the same process can be followed for each bird in a simulated flock, the parameters for each bird being defined using the means and standard deviations of each parameter describing the mean individual. Calculating the daily nutrient intake required to meet the potential performance of each individual in terms of numbers of eggs produced over the production cycle would improve the possibility of optimizing the composition (and daily allocation, in the case of broiler breeders) of the feed offered to the flock. To achieve these goals, a comprehensive understanding of the factors influencing the attainment of sexual maturity in these birds, of the ovulatory cycle and how this changes during the laying cycle, and of the changes that occur in egg and body component weights over time is required. This article describes such a stochastic egg production model developed at Universidade Estadual Paulista (UNESP), Brazil. In this article, only the calculation of the nutrient requirements of flocks of laying hens and broiler breeders is described, with examples of these requirements for simulated populations having different potential outputs. No attempt has been made to use this information to predict food intake or the consequences on performance of situations where hens were unable to consume sufficient feed. The model was developed based on studies conducted at the Poultry Science Laboratory, UNESP, Brazil. One study was conducted with two strains of laying hens (Hy-Line W-36 and Isa brown) (Bendezu et al., 2018) and another with broiler breeders (Cobb) (Ferreira et al., 2016) to generate the equations and parameters used in the models described herein. An overall scheme of the egg production model is presented in Figure 1. Open in a separate window Figure 1. Flow diagram from the dynamic simulation model to estimate the nutritional requirements as a function of body protein weight and egg production.

Effect of probiotics on fecal excretion, colonization in internal organs and immune gene expression in the ileum of laying hens challenged with SalmonellaEnteritidis

A study was conducted to evaluate the supplementation of probiotics on Salmonella colonization in the ceca and various internal organs as well as immune response in laying hens challenged with Salmonella enterica serovar Enteritidis (SE). Thirty-two 46-wk-old White Leghorns (W-36) were housed individually in wired laying cages under 16L:8D lighting schedule. Hens were challenged individually with nalidixic acid resistant Salmonella Enteritidis (SENAR) after which time they were grouped into four treatments: T1 = SENAR unchallenged control, T2 = SENAR challenged control, T3 = SENAR challenged + 0.05% probiotics (Lactobacillus plantarum), and T4 = SENAR challenged + 0.1% probiotics. All hens, including T1, were euthanized and sampled for the liver with gall bladder (L/GB), ileum, ovary, spleen, and ceca on 7-days post-infection (dpi). Fecal screening was performed on individual hens at both 3 and 6 dpi. No difference was detected between the treatments in cecal SENAR enumeration, and the mean log 10 cfu/gm of SENAR in the ceca was 3.7 for all three treatments. The prevalence of SENAR was lowest for ovary in all treatments and was highest in the spleen. However, there were no significant differences among the treatments in the internal organs. There was no significant difference in the fecal shedding among the treatments on either 3 or 6 dpi, with incidence of positive feces higher at 3 dpi compared to 6 dpi (100vs. 70% to 80%). SENAR challenge resulted in significant upregulation (P < 0.05) of interleukin (IL)-1β, 6, 10, interferon gamma (IFN-γ), and toll-like receptor (TLR)-4 mRNA expression. Highest level of probiotics resulted in a significant decrease in IFN-γ and elevation of IL-6 and IL-10 gene expression in the ileum. However, IL-1B and TLR-4 gene expression were not different from the SENAR challenge control. This study reveals that there was important regulation of immune genes by probiotics supplementation.

An RFID-Based Automated Individual Perching Monitoring System for Group-Housed Poultry

Abstract. Perching is a natural behavior of poultry. Considerable research has been done to explore the relationship between group overall perch usage and well-being of laying hens. To quantify the potential cause-effect relationship on individual hens with different health or well-being status (e.g., keel bone deformation, foot pad lesion, social ranking) in a group, it is necessary to identify the perching behavior of individual birds. However, continuously monitoring individual birds in a group poses considerable challenges. To enable such research and potential commercial application, this study developed and validated a radio frequency identification (RFID) based automated perching monitoring system (APMS) for characterizing individual perching behaviors of group-housed poultry. The APMS consisted of an RFID module, a load cell module, and a round wooden perch. The RFID module was comprised of a high-frequency RFID reader, three customized rectangular antennas placed under the perch, and RFID transponders attached to the birds. The load cell module was comprised of a data acquisition system and two load cells supporting both ends of the perch. The daily number of perch visits (PV) and perching duration (PD) for individual birds were used to delineate perching behavior. Three identical experimental pens, five hens per pen, were equipped with the monitoring system. Two RFID transponders were attached to each hen (one per leg), and a distinct color was marked on the bird’s head for video or visual identification and validation. Performance of the APMS was validated by comparing the system outputs with manual observation and labeling over an entire day. Sensitivity and specificity of the system were shown to improve from 97.77% and 99.88%, respectively when using only the RFID module to 99.83% and 99.93% when incorporating weight information from the load cell module. Using this system, we conducted a preliminary trial on the relationship of perching behavior and body weight of laying hens, which revealed little effect of body weight but considerable variability in perching behavior among the individual hens. The study demonstrated that the APMS had excellent performance in measuring perching behaviors of individual birds in a group. The APMS offers great potential for delineating individual differences in perching behavior among hens with different social status or health conditions in a group setting. Keywords: Individual perching behavior, Laying hen, Load cell, Precision livestock farming, RFID, Welfare.

Evaluation of nesting behavior of individual laying hens in an enriched colony housing by using RFID technology

The US egg industry is progressively adopting alternative housing systems for laying hens. Provision of nesting places accommodates natural behaviors and may improve the welfare of the laying hen. However, some fundamental questions remain about nesting behaviors of hens under different housing conditions, which would impact system design and management. For instance, how long does a hen use nest per day for egg laying or nest exploration? How many hens nest simultaneously? In such schemes, information on hens’ behavioral and production responses of hens remains relatively sparse. The primary objective of this work was to demonstrate that RFID technology can be used to continuously quantify dynamic nesting behaviors of individual laying hens in a 60-hen enriched colony housing (ECH). Results show that hens spent on average 63.7±1.4 min (mean±SE) in the nest box and made 23.4±0.7 nest visits during a 16 h daily light period. Time spent in and visits to the nest box during the 6 h laying period accounted for 56% and 45% of the light-period value, respectively. Maximum nest occupancy was 29.0%±0.4%. Three distinct phases of egg production in nest boxes were observed: initial (1.5 h), peak (3.2 h, egg laying rate of 0.24±0.01 eggs/min), and late (1.3 h). The majority (95.1%±0.6%) of the daily eggs were laid in the nest box. Considerable variations in nesting behavior among individual hens and day-to-day variations for a given hen were observed. The RFID system will enable researchers to examine the impacts of resource allocations on nesting behaviors of laying hens in alternative hen housing. Keywords: animal welfare, egg production, RFID, alternative hen housing, individual behaviors DOI: 10.25165/j.ijabe.20191206.5129 Citation: Oliveira J L, Xin H W, Wang K L, Zhao Y. Evaluation of nesting behavior of individual laying hens in an enriched colony housing by using RFID technology. Int J Agric & Biol Eng, 2019; 12(6): 7–15.

Using Radio-Frequency Identification Technology to Measure Synchronised Ranging of Free-Range Laying Hens.

Simple SummaryFree-range laying hens can choose to be indoors or outdoors. Individual hens vary in their ranging choice and this behaviour could also be affected by their flock mates. Radio-frequency identification tracking of individual hens in experimental free-range pens with group sizes of 46–50 hens was used to study flock ranging patterns. Across the day, hens moved through the range pop-holes in the same direction as other hens above levels expected by random chance, termed ‘pop-hole-following’. Hens were also simultaneously indoors or outdoors with other specific hens more often than expected by random chance, termed ‘hen-pair association’. Chicks that were provided variable stimulatory and structural enrichments from 4 to 21 days showed higher pop-hole-following and hen-pair association than non-enriched birds. The individual birds within these small hen groups were behaving primarily as a cohesive flock which has implications for understanding the group-level behaviour of hens. Further research would analyse if similar social movement patterns were present in larger commercial free-range flocks and how early rearing environments may affect adult social behaviour.Free-range laying hen systems provide individuals a choice between indoor and outdoor areas where range use may be socially influenced. This study used radio-frequency identification technology to track the ranging of individually-tagged hens housed in six experimental free-range pens from 28 to 38 weeks of age (46–50 hens/pen). All daily visits to the range were used to study group behaviour. Results showed that 67.6% (SD = 5.0%) of all hen movements through the pop-holes outdoors or indoors were following the movement of another hen (‘pop-hole-following’) compared to only 50.5% of movements in simulated random data. The percentage overlap in time that all combinations of hen pairs within each pen spent simultaneously outdoors or indoors showed a median value of overlap greater than the 90th percentile of random data. Pens housing hens that had been provided variable enrichments from 4 to 21 days (n = 3 pens) showed higher ‘pop-hole-following’ behaviour and a higher percentage of hen-pair association compared to hens reared in non-enriched conditions (n = 3 pens). These results show that birds in each free-range pen were primarily a cohesive flock and early enrichment improved this social cohesiveness. These results have implications for understanding free-range flock-level behaviour.

Organic and inorganic selenium in Aseel chicken diets: Effect on production performance

SUMMARY The present study was planned to explore the effects of different selenium-supplemented diets on production performance in 4 varieties of Aseel chicken, including Lakha (LK), Mushki (MS), Peshawari (PW), and Mianwali (MW). The selenium (Se) from Se-enriched yeast (SY) and sodium selenite (SS) was supplemented into a corn-soybean meal basal diet at 0.3 mg/kg, whereas control diet had no supplemental Se. In total, 84 adult molted Aseel hens (50 wk old), 21 from each variety, were randomly assigned to 12 treatment groups in a 3 × 4 factorial arrangement of 3 Se diets (organic, inorganic, and control) and 4 Aseel varieties (LK, MS, PW, and MW), under a randomized complete block design (RCBD). Each treatment had 7 replicates with individual hens per replicate. Feed intake (FI), body weight (BW), egg production (EP), egg weight (EW), egg mass (EM), FCR/dozen eggs, and FCR/kg egg mass parameters were evaluated. The results indicated that the hens fed organic Se-supplemented diet showed greater (P

Real-time variations in body temperature of laying hens with increasing ambient temperature at different relative humidity levels.

In order to measure the real-time variations in body temperature with increasing ambient temperature (AT) at different relative humidity (RH) levels, 60 Jinghong laying hens (35-wk-old) were raised in 3 controlled climate chambers (10 cages with 2 birds per chamber). The RH was fixed at one of 3 levels comprising 35, 50, or 85%, and the AT was increased gradually by 1 degree per 0.5h from 18 to 35°C in the 3 chambers. The core temperature (CT) and surface temperature (ST) of the hens, as well as the AT in the 3 chambers were recorded at 3min intervals using mini temperature data loggers. The data were analyzed with a broken-line model to determine the inflection point temperature (IPT, the certain AT above which the body temperature of the hens started to change). The experiment was repeated 3 times on 3 d. The IPTs of the laying hens were 23.89 and 25.46°C based on ST and CT at 50% RH, respectively, which indicated that the upper critical temperature of the thermoneutral zone of hens may be a specific temperature between 23.89°C and 25.46°C. The IPTs of the laying hens were 24.11 and 25.20°C based on ST and CT at RH 35%, respectively, and 21.93 and 24.45°C at RH 85%. The RH significantly affected the IPT of ST (P < 0.001). The IPTs were higher at 35 and 50% RH than that at 85% RH (P < 0.05). The coefficients of variation for the IPTs between individual hens were 2.96 to 4.51, and coefficients of variation for the IPTs for the same bird measured on 3 d were 0.69 to 1.59, thereby indicating that this method for estimating the IPTs of hens is stable and repeatable, although more samples are needed. In conclusion, our results indicate that analyzing the real-time variation in body temperature with increasing AT is a reliable method for estimating the IPT to provide an important reference for regulating the temperature in poultry houses.

On-Farm Evaluation of an Automatic Enrichment Device with Maize Silage for Laying Hens

ABSTRACTChallenges in alternative housing for laying hens are barren functional areas such as winter gardens and the occurrence of behavioral disorders. Environmental enrichment is a measure to deal with these problems. Therefore, an enrichment device offering maize silage automatically was tested in two winter gardens on-farm. The use of the winter gardens and the times individual hens stayed there and occupied themselves with the maize silage were determined in a temporary preference test. The proportion of residing hens was significantly larger in the enriched winter garden. The mean time individual hens stayed in the enriched winter garden ranged from 02:16 ± 02:22 (mm:ss) to 03:17 ± 02:27, whereas the time ranged from 00:18 ± 00:32 to 00:59 ± 01:19 in the other winter garden (p < .05). Once the enrichment device ran in both winter gardens, no differences were found between the observed parameters. On average, the hens occupied themselves with the enrichment material for 03:50 ± 02:12 to 05:01 ± 03:06. Thus, based on its use and acceptance by the laying hens, the automatic device provided adequate environmental enrichment.

An RFID-Based Smart Nest Box: An Experimental Study of Laying Performance and Behavior of Individual Hens.

This study designed a radio-frequency identification (RFID)-based Internet of Things (IoT) platform to create the core of a smart nest box. At the sensing level, we have deployed RFID-based sensors and egg detection sensors. A low-frequency RFID reader is installed in the bottom of the nest box and a foot ring RFID tag is worn on the leg of individual hens. The RFID-based sensors detect when a hen enters or exits the nest box. The egg-detection sensors are implemented with a resistance strain gauge pressure sensor, which weights the egg in the egg-collection tube. Thus, the smart nest box makes it possible to analyze the laying performance and behavior of individual hens. An evaluative experiment was performed using an enriched cage, a smart nest box, web camera, and monitoring console. The hens were allowed 14 days to become accustomed to the experimental environment before monitoring began. The proposed IoT platform makes it possible to analyze the egg yield of individual hens in real time, thereby enabling the replacement of hens with egg yield below a pre-defined level in order to meet the overall target egg yield rate. The results of this experiment demonstrate the efficacy of the proposed RFID-based smart nest box in monitoring the egg yield and laying behavior of individual hens.

Laying hens’ preferences for nest surface type are affected by enclosure

The nest surfaces preferred by hens are inconsistent with those typically provided in commercial settings. However, little research has explored hens’ preferences for commercially available nest surfaces. Our objective was to compare hens’ preferences for two such surfaces – red smooth and yellow mesh plastic– either enclosed or unenclosed with curtains. We predicted that enclosed nests would be preferred, but that this may be offset by any preferences hens have for different surface types. After conventional rearing, 996 pullets were placed in 24 furnished cages (FC) at 15 weeks of age (large: 41,296 cm2; small: 20,880 cm2). In Phase 1, each FC had two nests, one with a yellow mesh plastic surface and one with a red smooth plastic surface (3368 cm2). In half of the FCs, both surfaces were enclosed with plastic red curtains (ENCL, n = 12). The remainder had both open surfaces (OPEN, n = 12). In Phase 2, all FCs were subsequently modified at week 28 to have one enclosed and one open surface, allowing us to titrate how much hens preferred surface against enclosure. Preference was inferred from where eggs were laid, the location of sitting, and the amount of time spent on each surface. Egg location was recorded from the first egg to week 36. Sitting behaviour was scan sampled during weeks 25–26 (Phase 1) and 34–35 (Phase 2). Focal hens were selected at week 20 and observed from week 22–24 (Phase 1) and 31–33 (Phase 2). Results were unexpected: in Phase 1, hens laid more eggs on red smooth mats than yellow mesh when they were OPEN (66.8 ± 1.8% vs. 31.2 ± 1.8%; P < 0.0001), but more on yellow mesh mats than red smooth if they were ENCL (62.1 ± 2.1% vs. 36.7 ± 2.1%; P < 0.0001). In Phase 2, when all FCs had one open and one enclosed nest, hens preferred to lay in the enclosed nest (59.5 ± 2.0% vs. 39.5 ± 1.9%; P < 0.0001) but more so if they also had previous experience of an enclosed nest (P < 0.0001). In Phase 2, individual hen behaviour did not show that one surface was preferred over the other, but did indicate preference for enclosure. Hens changed their preferred nesting site from Phase 1 when enclosure was modified to favour the enclosed nests. This demonstrates that nest enclosure is important regardless of surface or hens’ previous experiences, and that preference for a commercial nest surface depends on whether it is enclosed.

Relationship between welfare and individual ranging behaviour in commercial free-range laying hens

Laying hens housed in free-range systems have access to an outdoor range, and individual hens within a flock differ in their ranging behaviour. Whether there is a link between ranging and laying hen welfare remains unclear. We analysed the relationships between ranging by individual hens on a commercial free-range layer farm and behavioural, physiological and health measures of animal welfare. We hypothesised that hens that access the range more will be (1) less fearful in general and in response to novelty and humans, (2) have better health in terms of physical body condition and (3) have a reduced physiological stress response to behavioural tests of fear and health assessments than hens that use the range less. Using radio frequency identification tracking across two flocks, we recorded individual hens’ frequency, duration and consistency of ranging. We also assessed how far hens ventured into the range based on three zones: 0 to 2.4, 2.4 to 11.4 or >11.4 m from the shed. We assessed hen welfare using a variety of measures including: tonic immobility, open field, novel object, human approach, and human avoidance (HAV) behavioural tests; stress-induced plasma corticosterone response and faecal glucocorticoid metabolites; live weight, comb colour, and beak, plumage, footpad, and keel bone condition. Range use was positively correlated with plasma corticosterone response, faecal glucocorticoid metabolites, and greater flight distance during HAV. Hens that used the range more, moved towards rather than away from the novel object more often than hens that ranged less. Distance ranged from the shed was significantly associated with comb colour and beak condition, in that hens with darker combs and more intact beaks ranged further. Overall the findings suggest that there is no strong link between outdoor range usage and laying hen welfare. Alternatively, it may be that hens that differed in their ranging behaviour showed few differences in measures of welfare because free-range systems provide hens with adequate choice to cope with their environment. Further research into the relationship between individual range access and welfare is needed to test this possibility.