Selective Breeding to Improve Productive and Reproductive Performances and Survivability of Indigenous Sakini Chicken

Indigenous chickens are quite popular in Family Poultry Production System (FPPS) in Nepal, but are constrained with their low productive performance. The present study evaluated the productive and reproductive performance of Sakini chicken in different filial generations and sexes. In addition, research also aimed at understanding the effect of generations on above performances. Initially, base populations (G-0) of Sakini were maintained by collecting eight weeks old birds from different agro-ecologial zones of Nepal. Performance of the birds of G-0 was evaluated based on weekly body weight (12-24 weeks), laying performance, fertility, hatchability, hatch weight and survivability. Selected birds of base population (G-0) were used to produce first (G-1), second (G-2) and third (G-3) generations through selective breeding in each generation. Similarly, body weights at hatching, 12 weeks, 16 weeks, 20 week and 24 weeks were significantly (p<0.001) improved from G0 to G3 and were also significantly (p<0.001) differ for sex (males were always heavier than females). Likewise, there was significant (p<0.05) improvement in egg production (per hen per year), age at first lay (days), body weight at sexual maturity, egg number and egg weight at 90 days of laying in progressive generations. Fertility, hatchability and survivability significantly (p<0.05) improved in selected generations in comparison to base population, whereas, no significant difference was obtained within the different selected population. Thus, indigenous Sakini chicken under this experiment performed better with respect to survivability, fertility and hatchability in later generations that provides ample scope of advancing selective breeding activities within the indigenous population in order to bring significant improvement in the overall productive performance of Sakini chicken in Nepal

Various bone parameters are positively correlated with hen body weight while range access has no beneficial effect on tibia health of free-range layers

The aim of this study was to determine if body weight or range use has a significant impact on bone health in commercial free-range laying hens, and to correlate tibia bone quality parameters with individual range usage and body weight. A total of 30 Lohmann Brown hens at 74 wk of age were selected from a commercial free-range farm and were either classified as heavy (mean ± SEM body weight 2.11 ± 0.034 kg, n = 14) or light (1.68 ± 0.022 kg, n = 16) body weight, and also classified as rangers (accessed the range for 86.7% of available days, n = 16) or stayers (accessed the range for 5.00% of available days, n = 14). The left tibiae of all individuals were analyzed for morphological parameters using computed tomography, evaluated for bone breaking strength, and ashed to determine mineral composition. Keel bone scoring was performed based on observation. Data were analyzed using a 2 × 2 factorial ANOVA, and regression analysis was performed. There was no measurable effect of range usage on any of the tibia parameters investigated. The body weight was significantly correlated with tibia breaking strength (r = 0.59), tibia weight (r = 0.56), tibia length (r = 0.64), diaphyseal diameter (r = 0.61), and total tibia volume (r = 0.67). In conclusion, range access had no beneficial effect on bone health. The impact of internal hen house furnishing and movement on bone health needs further investigation

Energy efficiency of commercial free-range laying hens of different body weight and ranging activity

Within a free-range flock, some hens prefer to spend majority of their time in the shed, while others frequently access the range. Development of these sub-populations may be associated with different hen performance. Evaluation of energy efficiency of laying hens provides important knowledge for optimal egg production. The aim of this study was to determine net energy utilisation of these subpopulations obtained from a free-range system. Forty-eight Lohmann brown hens at 72weeks of age were selected from a commercial free-range farm and classified as heavy or light body weight (average 2.01kg and 1.68kg respectively, n=24) and as rangers (accessed the range on 84.1 % of the available days; n=24) or stayers (accessed tl1e range on 7.17% of available days; n=24). The energy efficiencies were evaluated in a close-circuit respiratory chamber system. Stayers had significantly higher metabolisable energy intake/bird/d/BW0.75 (0.852±0.019 vs 0.798±0.016 MJ/g; P=0.025), heat production/BW0.75 (0.637±0.069 vs 0.607±0.057 MJ; P=0.005), heat increment/BW0.75 (0.267±0.007 vs 0.237±0.006 MJ;P=0.005) and retained nitrogen/ bird/d (1.59±0.02 vs l.46±0.03g; P=0.023) compared to rangers. Light hens had significantly higher metabolisable energy intake/bird/d/BWo75 (0.854±0.019 vs 0.796±0.016 MJ/g; P=0.018), net energy intake/bird/d/BW0.75 (0.595±0.013 vs 0.551±0.012 MJ/g; P=0.032), retained energy/bird/d/BW0.75(0.225±0.013 vs 0.181±0.012 MJ; P=0.032) and lower heat production/bird/d (0.936±0.011 vs 1.003±0.012 MJ; P=0.002) than heavier hens. In conclusion, stayers required higher maintenance energy than rangers, and light rangers are more energy efficient than light stayers. Future research on determination of ideal body weight of layers in the freerange system would be beneficial

Unsupervised exploratory cluster analysis of free range laying hens to determine the use of aviary feed chains and range access

Clustering is a common data mining methodology used for improved subject understanding. The aim of this study was to identify sub-populations oflaying hens housed in an aviary system to understand the use of feeding chains which can affect hen performance and welfare. A total of 5,641 Lohmann Brown free-range laying hens placed amongst 3 commercial flocks equipped with a 3-tier aviary system were individually monitored using radio- frequency identification (RFID) technology. Individual body weights of all hens were obtained at 16, 22, and 72 weeks of age. K-Means cluster analysis optimised with the Calinski-Harabasz Criterion was performed. Hens of cluster 1 (n=2442 hens) spent significantly more time on the lower tier feeding chain (14.5 ± 2.36 hours/hen/day) compared to hens of cluster 2 (n=2083; 6.9 ±2.4 h/hen/day) and hens of cluster 3 (n=1116; 2.0 ± 1.9 h/hen/day), respectively (

Range usage or body weight has minor effect on the gastrointestinal passage rate of commercial free-range laying hen

Free-range flocks are composed of hens that prefer to spend the majority of their time in sheds, "stayers", and hens that prefer to spend the majority of their time on the range, "rangers". While it was previously shown that rangers and stayers differ significantly in egg production, the rationale and underlying mechanism for the different performance remains unknown (Ruhnke and Sibanda, 2018). Range usage may contribute to improved digestive organ development such as the gizzard due to the positive effects of coarse fibre and grit stones leading to an increased grinding activity, and subsequently a decreased passage rate resulting in an increased exposure time of nutrients to digestive enzymes and overall increased nutrient digestibility (Amerah et al. 2009; Hetland et al. 2004). On the other hand, body weight may influence passage rate, due to a larger digestive tract convolute and subsequently larger quantities of enzyme secretion, and a larger intestinal absorption surface

The association between range usage and tibial quality in commercial free-range laying hens

1. Bone tissue adapts continuously to metabolic calcium demands, as well as to external forces due to physical weight loading subject to hen movement. Limited calcium metabolism and, subsequently, its availability from the medullary bone, is a major factor contributing to reduced eggshell quality in hens in the late laying period (>60 weeks of age).60 weeks of age). 2. Increasing physical activity and biomechanical loading during hen rearing has been demonstrated to increase skeletal strength, enhancing bone mass as well as endocortical and periosteal bone metabolism. Presently, the consequences of range use during lay on bone quality characteristics in laying hens remain unknown. 3.The aims of this study were to characterise tibiotarsal bone indices and evaluate the impact of range access during lay on tibia bone quality in commercial free-range laying hens. 4. This exploratory study described and analysed the volumetric measurements, morphological mechanical and trabeculae indices of the tibiotarsal bone of 48 Lohmann Brown laying hens at 74 weeks of age. All bone parameters were obtained using micro-computed tomography and correlated with individual hen range use. 5. Range usage throughout lay was not associated with tibial trabecular architecture (bone volume and fraction, trabecular thickness, trabecular connectivity density and structural model index), or any other morphological characteristics (breaking strength, diaphyseal diameter, bone weight and bone mineral density) of the tibia (P > 0.05) when hens were 74 weeks of age. 0.05) when hens were 74 weeks of age. 6. The results demonstrated a large variation in individual bone characteristics and suggested that range usage was not associated with bone quality in commercial free-range laying hens used in this study. In conclusion, the bone health of free-range commercial laying hens may be positively impacted by other features, such as hen genetics, feed, the quality of pullet rearing, perch availability or other shed equipment, and the benefits of these variables exceed the benefit of range use

Egg corticosterone concentrations after acute stress exposure in free range hens with different range usage

Free range hens are exposed to various potential stressors including weather conditions and risk of predation (Gilani et al., 2014). Distress can result in impaired biological functions including reduced reproduction, immunity and growth (Palme, 2012). In order to investigate the impact of early range usage, corticosterone concentrations in egg albumen were measured in response to a stressor (manual handling and relocation) in free range hens

Validation of a Radio Frequency Identification (RFID) system for aviary systems

Radio Frequency Identification (RFID) technology has been used for animal behaviour and welfare research, to monitor animal location and resource utilization. The aim of this study was to develop and validate an in-house custom built ultra-high frequency (UHF) RFID system to be used on a commercial free-range egg farm with three-tier aviaries

Free-range laying hens: using technology to show the dynamics and impact of hen movement

Free-range laying hens are provided with the opportunity to access various structural areas, including open floor space, feed areas, water lines, next boxes, perches, aviary tiers, winter gardens and ranges. Different individual location preferences can lead to the development of hen subpopulations that are characterised by various health, welfare and performance parameters. Understanding the complexity of hen movement and hen interactions within their environment provides an opportunity to limit the disadvantages that are associated with housing in loose husbandry systems and aids in decision-making. Monitoring hen movement using modern technologies such as radio-frequency identification (RFID), optical flow patterns, image analysis and three-dimensional (3D) cameras allows the accumulation of big data for data mining, clustering and machine learning. Integrating individual-based management systems into modern flock management will not only help improve the care of under-performing hens, but also ensure that elite hens are able to use their full genetic potential, allowing an ethical, sustainable and welfare friendly egg production. This review highlights the dynamics and impact of hen movement in free-range systems, reviews existing knowledge relevant for feeding hens in non-cage systems, and outlines recent technological advances and strategies to improve the management of free-range laying hens

Body weight is associated with welfare, health and egg production status in commercial free-range laying hens

Free-range housing systems are known for their increased biosecurity risk due to the increased hen exposure to various pathogens. However, use of indoor structures such as aviary systems may also be a potential risk for keel bone damage and may impact feather cover due to the increased exposure to other hens. Hen body weight is known to influence hen health, the immune system, and hen ovulation rate, but also the behaviour of an individual hen and may subsequently increase or decrease the likelihood of pathogen infection (Kilpinen et al., 2004). The aim of this study was to assess the welfare, health and egg production status of hens with different body weight in commercial free-range laying hens