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Hen breed and age are key factors influencing egg quality. In this study, 250 eggs were categorised into five groups: Lohmann Pink‐shell (LMP, 50 ± 2 weeks), Dongxiang Green‐shell (DXG, 50 ± 2 weeks), Dongxiang Pink‐shell (DXP, 50 ± 2 weeks), first‐laid Dongxiang Green‐shell (DXGF, 23 ± 1 week), and first‐laid Dongxiang Pink‐shell (DXPF, 23 ± 1 week). We compared egg quality traits, biochemical parameters, chemical composition, and amino acid profiles across these groups. Average egg weights were 59.89 g (LMP), 52.11 g (DXG), 59.45 g (DXP), 42.01 g (DXGF), and 42.56 g (DXPF). Yolk colour scores were higher in DXGF (13.72) than in LMP, DXG, and DXP (12.93, 12.72, and 12.81, respectively; p < 0.05). Egg yolk high‐density lipoprotein (HDL) levels were lower in LMP, DXG, and DXP (0.0316, 0.0390, and 0.0334 mmol/g, respectively) than in DXGF and DXPF (0.0411 and 0.0424 mmol/g; p < 0.05). Yolk crude fat was higher in DXG, DXP, DXGF, and DXPF (50.00%, 49.29%, 49.54%, and 49.93%, respectively) than in LMP (47.70%; p < 0.05). The EAA/TAA ratios in yolk ranged from 54.53 to 55.33, while those in albumen ranged from 53.38 to 53.71. Overall, this study demonstrates that hen breed and age significantly affect egg quality, biochemical traits, and amino acid composition. These findings may guide consumer egg selection and support the conservation and efficient utilization of chicken genetic resources. Hen breed and age – Lohmann Pink‐shell (LMP), Dongxiang Green‐shell (DXG), Dongxiang Pink‐shell (DXP), first‐laid Dongxiang Green‐shell (DXGF), and first‐laid Dongxiang Pink‐shell (DXPF) – significantly influence egg quality, biochemical traits, and amino acid composition, with yolk EAA/TAA ratios of 54.53–55.33 and albumen ratios of 53.38–53.71.

Studies on the prevalence of feather pecking in different commercial laying hen systems and its welfare and economic impacts are reviewed in the following paper. Current methods for controlling feather pecking include beak-trimming and alterations to light regimes, but these methods have significant disadvantages from the perspective of bird welfare. A substantial body of research has now identified risk factors for feather pecking during both the rearing and laying periods. It is argued that these findings can be translated into optimised management practices that can prevent and control feather pecking whilst simultaneously conferring welfare benefits. The genetic basis of feather pecking is considered, and studies that suggest group selection techniques could produce birds with a reduced tendency to feather peck in commercial flocks are highlighted.

Background The energy/protein imbalance in a low-protein diet induces lipid metabolism disorders in late-phase laying hens. Reducing energy levels in the low-protein diet to adjust the energy-to-protein ratio may improve fat deposition, but this also decreases the laying performance of hens. This study investigated the mechanism by which different energy levels in the low-protein diet influences liver lipid metabolism in late-phase laying hens through the enterohepatic axis to guide feed optimization and nutrition strategies. A total of 288 laying hens were randomly allocated to the normal-energy and normal-protein diet group (positive control: CK) or 1 of 3 groups: low-energy and low-protein diet (LL), normal-energy and low-protein diet (NL), and high-energy and low-protein diet (HL) groups. The energy-to-protein ratios of the CK, LL, NL, and HL diets were 0.67, 0.74, 0.77, and 0.80, respectively. Results Compared with the CK group, egg quality deteriorated with increasing energy intake in late-phase laying hens fed low-protein diet. Hens fed LL, NL, and HL diets had significantly higher triglyceride, total cholesterol, acetyl-CoA carboxylase, and fatty acid synthase levels, but significantly lower hepatic lipase levels compared with the CK group. Liver transcriptome sequencing revealed that genes involved in fatty acid beta-oxidation ( ACOX1 , HADHA , EHHADH , and ACAA1 ) were downregulated, whereas genes related to fatty acid synthesis ( SCD , FASN , and ACACA ) were upregulated in LL group compared with the CK group. Comparison of the cecal microbiome showed that in hens fed an LL diet, Lactobacillus and Desulfovibrio were enriched, whereas riboflavin metabolism was suppressed. Cecal metabolites that were most significantly affected by the LL diet included several vitamins, such as riboflavin (vitamin B 2 ), pantethine (vitamin B 5 derivative), pyridoxine (vitamin B 6 ), and 4-pyridoxic acid. Conclusion A lipid metabolism disorder due to deficiencies of vitamin B 2 and pantethine originating from the metabolism of the cecal microbiome may be the underlying reason for fat accumulation in the liver of late-phase laying hens fed an LL diet. Based on the present study, we propose that targeting vitamin B 2 and pantethine (vitamin B 5 derivative) might be an effective strategy for improving lipid metabolism in late-phase laying hens fed a low-protein diet.

Background The increasing trend of ban on the use of antibiotic growth promoters (AGPs) across the globe in the poultry industry has led to a growing need for alternatives to AGPs. Prebiotic, probiotic and their combination as a synbiotic have been considered as potential alternatives. This study aimed to investigate the effects of a prebiotic (isomaltooligosaccharide, IMO), a probiotic (PrimaLac®), and their combination (synbiotic) on hen performance, biochemical and haematological responses, and relative organ weights from 20 to 52 weeks of age. Results Supplementation of 1% IMO (PRE), 0.1% PrimaLac® (PRO) and 1% IMO + 0.1% PrimaLac® (SYN) improved ( P  < 0.05) feed intake and egg production at 20–36 weeks of age; body weight gain, feed conversion ratio and egg mass at 20–36 and 20–52 weeks of age; and egg weight at 20–36, 37–52 and 20–52 weeks of age. Compared to control-fed hens at 20–36 weeks of age, PRO- and SYN-fed hens produced less ( P  < 0.05) small size eggs while SYN-fed hens produced more large size eggs. From 37 to 52 weeks of age, PRE-, PRO- or SYN-fed hens produced less ( P  < 0.05) medium size eggs, and more large and extra-large size eggs. PRE, PRO or SYN supplementation decreased ( P  < 0.05) the serum total cholesterol at 36 weeks of age, and serum low-density lipoprotein (LDL) cholesterol, alanine aminotransferase (ALT) and alkaline phosphatase (ALP) at 36 and 52 weeks of age. At 36 and 52 weeks of age, supplementation of PRE, PRO or SYN increased ( P  < 0.05) lymphocyte percentage and decreased ( P  < 0.05) heterophil percentage, leading to a lower heterophil to lymphocyte (H/L) ratio. No significant differences were observed in the relative weights of the heart, liver, ovary, pancreas and spleen of all dietary treatment groups. Conclusions Supplementation of PRE, PRO or SYN improved performance, serum total cholesterol, LDL cholesterol, ALT, ALP and H/L ratio of hens from 20 to 52 weeks of age. These results demonstrated the use of PRE, PRO and SYN as alternative feed additives to AGPs for improving the health and productivity of hens, while PRO is the best for commercial layer production to yield maximum profit.

The aim of this study was to determine the effects of molting programs and Humulus (Humulus lupulus) plant on tibia characteristics and expression of TRPV6 gene in Pre, during and post-molting layers. Experiment 1, Hy-line W-36 (75-76 weeks, n= 272) laying hens 20 hens slaughtered before molting at end of 76 week for checking status. Experiment 2, A total of 252 Hy-line W-36 were managed in 7 treatments, 6 replicates and 6 birds in each. Treatments including: (A) feed withdrawal (FW), (B) basal diet + 2% Portulaca oleracea plant powder, (C) basal diet + 30% sunflower seed hulls + 2% Portulaca oleracea powder, (D) basal diet + 2% white button mushroom waste, (E) basal diet + 30% sunflower seed hulls + 2% white button mushroom waste, (F) basal diet + 30% sunflower seed hulls and (G) basal diet (Control treatment). Experiment 3, A total hens of treatments in experiment 2 after slaughter of 20 hens maintained for experiment 3, then each treatment diet was modulated in to two treatments (with and without Humulus). In this step, this 224 Hy-Line W-36 laying hens were designed by 14 treatments, 4 replicates and 4 hens in each in a 7×2 factorial arrangement with completely randomized design (CRD). The highest tibia weight and bone cortical thickness were observed in the treatment contain Portulaca Oleracea powder (p < 0.05). A higher tibia weight, bone cortical thickness, ash and density were indicated by Humulus plant in post-molting periods (p < 0.05). The bone cortical thickness and ash were increased by basal diet + 30% sunflower seed hulls + 2% Portulaca Oleracea powder and basal diet + 30% sunflower seed hulls treatments at post molting periods (p < 0.05). During the post-molting period, there was no significant effect on maximum strain and elastic modulus by Humulus and molting methods (p > 0.05). Also, no significant differences were found in expression of TRPV6 mRNA in the jejunum, kidney and egg shell gland (ESG) during molting and post-molting periods (p > 0.05). In conclude, improve tibia characteristics during molting and post-molting periods by Portulaca oleracea powder and white button mushroom waste Moreover, Humulus plant improved tibia status without affecting TRPV6 mRNA expression.

The number and size of free-range laying hen (Gallus gallus domesticus) production systems are increasing within Australia in response to consumer demand for perceived improvement in hen welfare. However, variation in outdoor stocking density has generated consumer dissatisfaction leading to the development of a national information standard on free-range egg labelling by the Australian Consumer Affairs Ministers. The current Australian Model Code of Practice for Domestic Poultry states a guideline of 1500 hens/ha, but no maximum density is set. Radio-frequency identification (RFID) tracking technology was used to measure daily range usage by individual ISA Brown hens housed in six small flocks (150 hens/flock – 50% of hens tagged), each with access to one of three outdoor stocking density treatments (two replicates per treatment: 2000, 10 000, 20 000 hens/ha), from 22 to 26, 27 to 31 and 32 to 36 weeks of age. There was some variation in range usage across the sampling periods and by weeks 32 to 36 individual hens from the lowest stocking density on average used the range for longer each day (P<0.001), with fewer visits and longer maximum durations per visit (P<0.001). Individual hens within all stocking densities varied in the percentage of days they accessed the range with 2% of tagged hens in each treatment never venturing outdoors and a large proportion that accessed the range daily (2000 hens/ha: 80.5%; 10 000 hens/ha: 66.5%; 20 000 hens/ha: 71.4%). On average, 38% to 48% of hens were seen on the range simultaneously and used all available areas of all ranges. These results of experimental-sized flocks have implications for determining optimal outdoor stocking densities for commercial free-range laying hens but further research would be needed to determine the effects of increased range usage on hen welfare.

This study analyzed the productive performance, egg quality and physiological and behavioral parameters of laying hens at different housing densities in a cage-free system, following animal welfare guidelines and improvements in animal housing in intensive systems. 252 Novogen Brown laying hens, 52 weeks old and with an average weight of 1,740 ± 0.11 kg, were used over 63 days, divided into three periods of 21 days. The study adopted a completely randomized experimental design, with four treatments and seven replications. The housing densities tested were: 6 birds box-1 (0.406 m2 bird-1), 8 birds box-1 (0.305 m2 bird-1), 10 birds box-1 (0.244 m2 bird-1) and 12 birds box-1 (0.203 m2 bird-1 bird). The data were analyzed for normality of residuals, homogeneity of variance and independence of errors, using linear and quadratic regression models for each variable. In cage-free poultry production systems, housing densities of 6 to 8 birds per box can be used without affecting performance, egg quality, physiological or behavioral parameters of the hens.

Objectives: Lead (Pb), a toxic heavy metal, is a serious concern for poultry that negatively affects their productivity and health. To combat those issues efficiently, it is necessary to include feed supplements that have rich antioxidant properties for satisfactory health and productivity. Spirulina platensis (Sp), a microalgae, is a compound that provides several health benefits for humans and animals. This study explores that supplementation of Sp in diet as well as in water reduces the burden of Pb in different tissues, improves hematology, and improves the productive performance of advanced-age laying hens. Materials and methods: Forty birds were separated into four groups: the control (C), Spirulina (Sp), Pb, and (Pb + Sp) groups. The Pb group was given Pb acetate at a dose of 2 gm/l in water ad libitum for 4 weeks. Sp group was fed Sp at a dose of 4 gm/kg feed. The Pb + Sp group was given Pb and Sp as in the previous groups. Results: Productive performance and hematology such as hemoglobin (Hb), packed cell volume, red blood cell, mean corpuscular volume, mean corpuscular Hb (MCH) concentration, and MCH were significantly (p < 0.05) decreased in Pb-treated groups compared to controls. The distribution of Pb concentration was highest in the bones and lowest in the gizzard. However, Sp treatment significantly (p < 0.05) increased the productive performance and the hematological parameters. Moreover, Pb concentration in different organs significantly decreased in the group treated with Sp. Conclusion: This study indicates that Sp can possibly be used as a natural and powerful dietary additive to mitigate heavy metal intoxication in chickens, thereby being efficient and effective for production.

In the European research project HealthyHens, welfare indicators as well as husbandry and management conditions were recorded in 107 organic laying hen farms in eight countries. Farms were visited at peak and end of lay. Egg production was on average comparable to breeder specifications. A mean mortality of 5.7% and mean prevalences of footpad lesions of 30.5%, keel bone damage of 44.5%, 57.3% of flocks with on average >200 Ascarid eggs per gram faeces and 28.2% of flocks with >100 mites/trap were recorded. A large variation between flocks indicated options for improvement. Based on the results, the following measures can be recommended: (i) decreasing mite and worm infestation and (ii) providing an attractive covered veranda, because of their association with decreased mortality; (iii) maximising access to the free range, because of its relation to decreased A. galli infection and less injurious pecking; (iv) feeding sufficient protein levels and (v) providing adequate litter as preventive measure against feather pecking and cannibalism; (vi) ensuring that the birds have sufficient weight and (vii) preventing accidents by adequate hen house facilities and light conditions to reduce keel bone damage. These primarily management-based measures have the potential to improve bird welfare both in terms of behavioural and health aspects.

Propolis (PR) is a resin product of bee colonies that has rich bioactive antioxidant and bactericidal compounds. Endotoxin, a byproduct of bacterial growth, is reported to cause progressive induction of endogenous oxidative stress and has negative impacts on individual health and wellbeing. Hereby, we investigated the ability of PR to alleviate the oxidative stress and immunosuppression imposed by avian pathogenic Escherichia coli using laying hen as a based model. In this study, PR was dietary supplemented to hens for 4 weeks at a concentration of 0.1%. At the beginning of the 4th week of the experiment, hens from control and PR treatment were injected with E. coli (O157:H7; 107 colonies/hen) or saline. The results showed significant (p < 0.05) negative impact of E. coli challenge on antioxidant status, immune response and productive performance. PR supplementation reduced (p < 0.05) inflammation markers levels (tumor necrosis factor α (TNFα) and interleukin 1β (IL-1β)) and plasma corticosterone concentration. The antioxidant status was ameliorated with dietary PR supplementation to challenged hens, showing significant (p < 0.05) reduction in malondialdehyde (MDA) levels and increasing total antioxidant capacity (TAC) concentrations. Cell mediated, as well as, humeral immune response improved significantly (p < 0.05) with dietary PR verified by the enhancement of T- and B-lymphocyte proliferation and the positive respond to phytohemagglutinin (PHA). Leucocyte cells viability increased significantly and the apoptotic factor forkhead box O3 (Foxo3) was reduced with PR supplementation. The current study revealed that dietary PR supplementation can effectively be used as an organic feed additive to overcome the endogenous oxidative stress induced by endotoxins challenge.