Poultry

Stocking density is one of the major concerns in all production systems, which is why lawmakers, retailers, and consumers are increasingly concerned about this issue and its relation to animal welfare. The aim of this study was to identify if stocking density had an effect on white egg layer production, egg quality, bird health, and welfare parameters. For this study, five stocking densities were evaluated in colony cages: 1342 cm²/hen, 897 cm²/hen, 671 cm²/hen, 535 cm²/hen, and 445 cm²/hen. Egg production and physical egg quality were measured. Hen health and welfare parameters including corticosterone levels, H/L, oxidative stress pathways, jejunum tight junction protein expression, bone health, gut histology, body condition, and cytokine expression were evaluated. The results from this indicated that higher stocking densities resulted in lower production but larger eggs, while feed efficiency remained unaffected. Furthermore, physical egg quality parameters also remained unaffected. When stress and welfare parameters were analyzed, this research identified that decreasing stocking density did not affect jejunum oxidative stress pathways, pro-inflammatory cytokine expression, bone health, or intestinal health. At the final sampling period (69 weeks), the highest stocking density demonstrated higher corticosterone concentrations and IL-10 expression compared to the lowest stocking density. Furthermore, feather scores were found to be poorer as density increased. Finally, the highest density had higher Hansen’s test scores compared to other densities, which indicates a greater fear response. In conclusion, it appears that decreasing stocking density may provide some benefits in production and welfare to commercial egg layers, particularly at the end of the laying cycle. Full article

The amount of space provided to laying hens has been an animal welfare topic of concern from consumers, special interest groups, and lawmakers. The freedom to perform normal behaviors is one component of animal welfare, and, therefore, the objective of this study was to assess behavior at different stocking densities. Shaver White laying hens were housed in colony cages at five stocking densities. Video recordings of three cages/treatment were taken at 30, 46, and 62 weeks of age in the morning, afternoon, and night. At each age, a 20 min segment of video from each time of day was analyzed. Every minute was annotated to identify the behavior that hens spent the majority of their time performing. Data were averaged to calculate the percentage of hens engaged in each behavior per cage. The total count of aggressive bouts was recorded across the 20 min period. Data were analyzed with a general linear model utilizing the variables time of day, density, age, and the full factorial of interactions. Intermediate stocking densities displayed the lowest percentage of crouching (p = 0.009) and aggressive acts per hen (p < 0.0001). Hens stocked at 1341.93 cm² walked the most (p < 0.0001). Hens were seen standing and preening (p < 0.0001) more in the morning, crouching and sham dust bathing (p < 0.0001) more in the afternoon, stretching less while feeding and drinking, and being more aggressive at night (p < 0.0001). Finally, as hens aged, they began to stand and crouch more (p < 0.0001) and preen (p = 0.013), walk (p < 0.0001), and demonstrate aggressive behaviors (p = 0.007) less. In conclusion, the majority of behaviors assessed were not influenced by stocking density. However, the different amounts of aggression between the treatments could indicate higher stress and frustration, which warrants more investigation. Full article

Limited published data areavailable on the current DLys requirements of Hy-Line Silver-Brown layers. The effects of energy (AMEn) and standardized ileal digestible lysine (DLys) concentration on the performance of Hy-Line Silver-Brown layers were studied from 20 to 35 weeks of age. The experimental design was randomized with twenty-four dietary treatments arranged as a 2 × 12 factorial with two AMEn concentrations (2750 and 2900 kcal/kg feed) and twelve levels of DLys (4.2, 4.5, 4.8, 5.1, 5.4, 5.7, 6.0, 6.6, 6.3, 6.9, 7.2, and 7.5 g/kg). Total egg weight (TEW), average egg weight, total egg number (TEN), laying rate, total feed intake, average daily feed intake (ADFI), mortality, hen body weight, hen body weight gain, eggshell thickness, eggshell breaking strength, yolk weight, albumen weight, and eggshell weight were recorded. An increase in energy content from 2750 to 2900 kcal AMEn/kg reduced ADFI (p < 0.001), egg mass output (p = 0.042), and feed conversion ratio (p = 0.018, g/g; p = 0.001, g/dozen) and increased the fat percentage in the liver (p = 0.028). An increased DLys intake from 529 to 882 mg/hen/day increased the TEN (p = 0.001), TEW (p < 0.001), and egg mass output (p < 0.001); improved the feed conversion ratio (p < 0.001); and reduced carcass (p = 0.001) and liver fat percentage (p = 0.05). Hy-Line Silver-Brown hens require no more than 780 mg (optimized egg production) and 880 mg (maximized egg weight) DLys/hen/day during pre-peak and peak production phases. Full article

This study evaluated the effects of natural pigments, such as paprika extract and marigold flower extract, on performance, egg quality, carotenoid content in the yolk, and shelf life of Japanese quail eggs. The experiment included 160 birds, divided into 4 treatment groups, as follows: 0.8% paprika extract, 0.8% marigold flower extract, 0.8% paprika/marigold (P/M) mixture, and a control group. The experiment lasted 84 days. The inclusion of paprika, marigold, or their combination did not affect performance parameters, except for feed conversion, which was significantly poorer in the supplemented groups compared to the control. An improvement in yolk color was observed, particularly in the marigold group, which showed higher concentrations of β-carotene (40 g/kg). Yolk color intensity, measured using the L*, a*, and b* scales, was enhanced in all supplemented groups. During storage, yolk weight increased after 5.72 days, while albumen weight showed a significant reduction starting at 4.30 days, with a more pronounced decrease after 6.6 days. Albumen diameter expanded after 15.7 days of storage, and the Haugh unit was significantly affected from the 17th day onward. Yolk percentage decreased after 4.06 days, while albumen and eggshell percentages decreased after 4.10 and 3.41 days, respectively. These results suggest that paprika and marigold extracts are effective in improving yolk color and maintaining egg quality without compromising performance. However, a poorer feed conversion by mass was observed in the groups fed with the paprika, marigold, and the (P/M) mixture, compared to the control group. These natural pigments also positively impacted egg quality, particularly in terms of color intensity and internal parameters, and helped maintain egg quality during storage, meeting consumer expectations for high-quality products. Future studies should focus on evaluating the antioxidant effects of these pigments in eggs, as this could provide a deeper understanding of their potential benefits, both in terms of nutritional quality and shelf-life enhancement. Full article

The application of chemical additives in poultry litter management aims to control the microbial population and reduce harmful gases. We conducted in vitro analyses to determine and compare the minimum inhibitory concentration (MIC) of commercial chemical additives of calcium oxide, aluminum sulphate, and copper sulphate on bacteria such as Salmonella Enteritidis, Salmonella Infantis, Salmonella Heidelberg, Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa; yeast (Candida albicans); and fungi (Aspergillus flavus and Penicillium citrinum). The minimum bactericidal concentration (MBC) and minimum fungicidal concentration (MFC) were also evaluated. Chemical additive solutions were prepared at a concentration of 0.1 g/mL and diluted up to 0.00078 g/mL, corresponding to concentrations from 10 kg/m² to 0.07 kg/m² when the additives were applied to the litter. In general, aluminum sulphate inhibited the growth of bacterial and fungal strains at a concentration of 0.62 kg/m² (6.25%). On the other hand, additives based on copper sulphate and calcium oxide showed an inhibitory effect on bacterial and fungal strains at dosages above 2.5 kg/m² and 5 kg/m², respectively. Research into commercially available poultry products is rare but important for determining the correct dosage of chemical additives to control the microbial and fungal population of poultry litter. The use of a correct dosage can prevent microbial resistance to chemical additives. This study continues to analyze the use of additives on commercial farms. Full article

Monitoring Campylobacter and antimicrobial resistance is critical, as its presence in the food chain, particularly in poultry, represents a serious threat to public health. However, despite its significant impact, this bacterium remains largely underestimated and under-surveilled in many countries, including Morocco. The current study aims to understand the occurrence of Campylobacter spp. in different poultry production systems, highlighting the importance of continuously monitoring antimicrobial susceptibility in these bacteria. For this purpose, 300 poultry samples were collected from a slaughterhouse and 254 from traditional markets in the Rabat-Salé-Kénitra region. The research on Campylobacter was performed according to the standard ISO10272-1(2017), and the confirmation of Campylobacter species was carried out using MALDI-TOF mass spectrometry. Additionally, the disk diffusion method was employed to assess antimicrobial susceptibility, and conventional PCR was utilized to detect the presence of the tet(O) gene in tetracycline-resistant strains. Out of 554 samples collected, 159 (28.7%) tested positive for Campylobacter, of which 84% were identified as Campylobacter coli and 16% as Campylobacter jejuni. Moreover, the results revealed a notably higher detection of Campylobacter in traditional markets (41.33%) than in slaughterhouses (19.85%). Additionally, it was more prevalent in chicken samples (35.37%) than in turkey samples (22.02%). Campylobacter resistance to antimicrobials revealed a resistance rate of 99% to ciprofloxacin, 73% to ampicillin, 82% to tetracycline, 29% to erythromycin, and 0% to gentamicin, as well as to the association of amoxicillin and clavulanic acid. Among the strains with a phenotypic resistance profile to tetracycline, 80% carried the tet(O) gene. The results provide an overview of the current state of antibiotic resistance in Campylobacter in Morocco. They underline the urgent need for the prudent use of antimicrobials and may encourage further research into the development of new antimicrobial agents. They also highlight the importance of raising awareness of the risk of carcass contamination Full article

A study was conducted using 144 Hy-Line Brown laying hens (22 weeks old) to assess the impact of exogenous enzymes on energy utilisation and ileal nutrient digestibility in diets containing 300 g/kg wheat distillers’ dried grains with solubles (DDGS). A basal diet was prepared and divided into eight treatments: a control (C) and diets supplemented with 2000 units/kg xylanase (XYL), 500 units/kg phytase (PHY), and 4000 units/kg protease (PRO), individually and in combination. The diets were fed for nine days to six coops, each housing three birds. Feed intake, weight gain, and feed conversion ratio were recorded. The feed and excreta were analysed for gross energy, and the apparent metabolisable energy (AME) was calculated. On the final day, the birds were euthanised, and ileal digesta were collected, freeze-dried, and analysed for the digestibility coefficients of dry matter (DM), nitrogen, fat, and neutral detergent fibres (NDFs). XYL supplementation improved (p = 0.035) dietary AME but did not affect (p > 0.05) DM, nitrogen, fat, or NDF digestibility. No significant effects (p > 0.05) were observed for PHY or PRO, and no interactions (p > 0.05) were found between enzyme combinations. Substrates in experimental diets involving various enzyme combinations should be given careful consideration. Full article

Dermanyssus gallinae, Ornithonyssus sylviarum, and Ornithonyssus bursa are ectoparasitic bird mites that affect both avian hosts and humans, causing economic losses in poultry farming and dermatological issues in humans. Due to their small size and transient feeding behaviour, mite-induced dermatitis is often misdiagnosed. In this study, over 4900 cases of entomodermatoses, recorded at the Urania Research Centre and the Department of Veterinary Medicine of Perugia—Parasitology Section between 2010–2024, were analysed, selecting cases linked to bird mites. Data on lesion onset, timing, infestation location, environmental factors, lesion type, and symptoms were examined. Avian Dermanyssoidea mites were responsible for about 4% of dermatological cases, with D. gallinae and O. sylviarum being the most prevalent, while O. bursa was less frequent. Species identification was also based on the morphology of the chelicerae and palps, with cases peaking in spring and summer. These mites were widely distributed across Italy, and Ornithonyssus species caused more severe skin reactions than Dermanyssus. Infestations often involved both genera. This study provides the first large-scale analysis of bird mite infestations in Italy, offering new insights into their distribution, infestation dynamics, and clinical symptoms. The findings contribute to improving diagnostic accuracy, pest control strategies, and public health interventions. Full article

The relentless drive to meet global demand for poultry products has pushed for rapid intensification in chicken farming, dramatically boosting efficiency and yield. Yet, these gains have exposed a host of complex welfare challenges that have prompted scientific scrutiny and ethical reflection. In this review, I critically evaluate recent innovations aimed at mitigating such concerns by drawing on advances in behavioral science and digital monitoring and insights into biological adaptations. Specifically, I focus on four interconnected themes: First, I spotlight the complexity of avian sensory perception—encompassing vision, auditory capabilities, olfaction, and tactile faculties—to underscore how lighting design, housing configurations, and enrichment strategies can better align with birds’ unique sensory worlds. Second, I explore novel tools for gauging emotional states and cognition, ranging from cognitive bias tests to developing protocols for identifying pain or distress based on facial cues. Third, I examine the transformative potential of computer vision, bioacoustics, and sensor-based technologies for the continuous, automated tracking of behavior and physiological indicators in commercial flocks. Fourth, I assess how data-driven management platforms, underpinned by precision livestock farming, can deploy real-time insights to optimize welfare on a broad scale. Recognizing that climate change and evolving production environments intensify these challenges, I also investigate how breeds resilient to extreme conditions might open new avenues for welfare-centered genetic and management approaches. While the adoption of cutting-edge techniques has shown promise, significant hurdles persist regarding validation, standardization, and commercial acceptance. I conclude that truly sustainable progress hinges on an interdisciplinary convergence of ethology, neuroscience, engineering, data analytics, and evolutionary biology—an integrative path that not only refines welfare assessment but also reimagines poultry production in ethically and scientifically robust ways. Full article

Rearing broiler chickens generates large quantities of waste material in the form of bedding. Anaerobic digestion (AD) is a technology that can be applied to this waste. This study aimed to evaluate the AD of broiler litter, either screened (S) or unscreened (US), from different flocks, collected from each production batch, totaling nine, from a commercial farm. Anaerobic digestion was conducted in batch biodigesters, and fraction separation was performed through screening prior to loading. The S substrate from the second and fifth flocks did not produce biogas. Reductions in total (TS) and volatile solids were highest for S substrates from the third flock (50.5% and 58.3%, respectively). Only the third flock’s S substrates showed greater reductions in solids than the US substrates. Potential biogas and methane production were also highest in the third flock’s bedding for both the S substrate (336.8 and 218.2 L/kg of TS, respectively) and the US substrate (296.8 and 213.4 L/kg of TS, respectively). The methane concentration in the S substrate was highest in the third flock (64.8%), while in the US substrate, it was highest in the third and fourth flocks (70.3%). Screening the litter reduced the process efficiency. We conclude that fraction separation is inadvisable for broiler litter. Full article

The objective of this study was to evaluate the effects of free or microencapsulated trace mineral (TM) premixes at normal and high dietary inclusion levels on the internal and external quality and mineral composition of broiler breeder eggs. Twelve breeder pens were randomly assigned to one of four treatments consisting of a factorial arrangement of two TM premix forms (free and microencapsulated) and two dietary inclusion levels of TM premix (100% and 300% of Aviagen recommendations). Hens fed the microencapsulated TM had significantly greater vitelline membrane strength than those fed the free TM (1.92 g vs. 1.81 g, respectively (p < 0.05)). Hens fed high dietary TM levels produced eggs with significantly greater shell elasticity and yolk color than hens fed the lower TM inclusion level (0.224 mm vs. 0.247 mm, and 8.89 vs. 8.62, respectively (p < 0.05)). Only the whole-egg Mn concentration was observed to be significantly (p < 0.01) increased by the higher dietary inclusion level of TM compared to lower (0.0301 mg/g vs. 0.0248 mg/g, respectively (p < 0.01)). There were no treatment effects on eggshell mineral composition. Regardless of the dietary inclusion level, feeding broiler breeders microencapsulated TM does have some beneficial effects on the internal egg quality properties, whereas increased dietary TM supplementation levels improve the shell quality, yolk color index, and whole-egg Mn concentration. There were no significant premix form X TM premix dose effects observed. Full article

Lipid matrix microencapsulation is hypothesized to improve bioavailability for broiler breeders supplemented with normal and protect against excessive levels of inorganic trace minerals. At 27 weeks (wk), nine females and two males were assigned to each of the 12 floor pens. Each pen was randomly assigned to dietary treatments (trt) in a factorial arrangement of two mineral premix forms, free (FRTM) and microencapsulated (MITM), and two mineral premix supplement dosages (100% and 300% of Aviagen recommendations). At 55 wk termination, 15 hens/trt were randomly selected to assess tibia and jejunum morphology. Breeders receiving MITM improved hen day % (HD %), hen housed (HH%), and FCR but produced the lightest chicks at hatch. The TM form had no significant effect on histology, but TM 100% had greater villus height (VH), crypt depth (CD), and villi area than TM 300% (p < 0.5). No significant treatment effects on bone weight, length, and bone mass density were observed. However, MITM treatments increased tibia thickness, and FRTM supplementation increased ash% and Cu content. Hens fed 300% TM had higher bone Mn content than 100% TM, whereas hens fed MI100 had the highest Fe content. Feeding lipid matrix microencapsulated trace minerals to broiler breeders does have positive impacts on the production of eggs, but no effects were observed in the histomorphology of the jejunum or tibia bone parameters. Full article

This study reports an outbreak of hepatitis-splenomegaly syndrome (HSS) in a color broiler parent stock flock in Bangladesh, marking the first known instance of HSS associated with avian hepatitis E virus (aHEV) genotype 7 outside Europe and only the second report of HSS in South Asia. The affected flock exhibited severe clinical signs, including a high cumulative mortality, reaching 31.6% in hens, and an abrupt decrease in egg production, dropping by over 20 percent. Histopathological analysis of liver and spleen samples revealed multifocal areas of necrosis, hemorrhages, and bacterial colonies. RT-PCR confirmed the presence of aHEV and immunohistochemistry showed signals within hepatic sinusoids and peri-ellipsoidal zones in the spleen. Complete genome sequencing of RNA from liver and bile samples on the Illumina platform established a pathogenic link to aHEV genotype 7. Despite aHEV’s known association with HSS, inconsistencies in disease manifestation suggest additional cofactors influencing pathogenesis, with secondary bacterial infections potentially contributing to clinical severity in this outbreak. Overall, this case expands the geographic distribution of aHEV genotype 7 and highlights the need for further epidemiological studies to investigate genotype–pathogenicity associations, especially in regions with limited prior data on HSS. Full article

Probiotics have been used to promote pioneer colonization by beneficial bacteria in poultry. The purpose of the present study (four trials) was to determine if an in ovo injection with Bifidobacterium saeculare (B2-2, B3-4) and/or lactic acid bacteria (LAB18, LAB46) at d18 of embryogenesis reduced Enterococcus and Gram-negative bacterial colonization in the gut at hatch. An environmental challenge model was used to simulate microbial contamination in large-scale hatch cabinets in a laboratory setting. In all trials, gut homogenates obtained from chicks at hatch were plated to enumerate relevant bacterial populations. Performance was evaluated in trials two and four. The top treatments in trial one were selected for further testing in trials 2–4. The significance level for all analyses was set at p < 0.05. A meta-analysis of gut bacterial recovery for trials 2–4 revealed that the administration of probiotic treatments increased LAB and/or bifidobacteria at hatch compared to non-treated groups. LAB46 + B2-2 was more effective at reducing Gram-negative bacteria and Enterococcus in the gut compared to other probiotic treatments. All treatments improved d14 BW and d0–14 BWG compared to non-treated groups. These results indicate that exposure to beneficial bacteria during late embryogenesis can prevent colonization by opportunistic pathogens associated with contamination in commercial hatch cabinets and may also improve early performance in broiler chickens. Full article

The presence and biological role of extracellular DNA (eDNA) have been explored in diverse microbial environments. Nonetheless, it has not been studied in the chicken gut microbiome. This study aims to investigate eDNA in the chicken cecum, analyzing cecal samples from broiler chickens using three preparation methods: Whole Cecal Suspension (WCS), Washed Cell Pellets (WCP), and Cell-Free Supernatant (CFS). The 16S rRNA gene-based microbiota analysis revealed distinct microbial communities in CFS compared to WCS and WCP (p = 0.001). Notably, specific taxa, including Anaerofilum, Anaerotruncus, Oscillospira, Syntrophomonas, and Delftia, were enriched in CFS. Confocal fluorescence microscopy, employing stains such as Propidium Iodide (PI), GelGreen, and SYTO 9, confirmed the presence of eDNA with filaments observed in WCS and CFS. Colocalization of PI and GelGreen™ validated the extracellular nature of eDNA, while DNase I treatment selectively degraded eDNA, further confirming its extracellular nature. Our findings in this study highlight the presence of eDNA in the chicken cecal microbiome, and the presence of eDNA associated with specific taxonomic groups suggest that it might play a specific role in the biological function of the cecal microbiome, which warrants further investigation in the future. Full article

Infectious bronchitis virus (IBV) is an enveloped, positive-sense, single-stranded RNA virus belonging to the genus Gammacoronavirus. It primarily infects avian species, causing respiratory and renal disease and irreversible damage to the oviduct, which can lead to high mortality rates in chickens. The lack of rapid and reliable diagnostic tools for on-farm IBV detection hampers timely disease management and control measures. The introduction of DNA biosensors offers a promising approach for the sensitive and specific detection of IBV, facilitating rapid identification and intervention. In this study, an electrochemical DNA biosensor with a multi-walled carbon nanotube (MWCNT)-modified gold electrode was developed for IBV detection. The biosensor targeted the target-specific 5′ untranslated region (5′-UTR) of the IBV genome. Under optimal conditions, the immobilization and hybridization efficiencies were evaluated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), with methylene blue as a redox indicator. The developed DNA biosensor demonstrated a dynamic detection range from 2.0 × 10⁻¹² to 2.0 × 10⁻⁵ mol L⁻¹, with a limit of detection (LOD) of 2.6 nM and a limit of quantification (LOQ) of 0.79 nM. Validation using a small subset of clinical samples, including crude complementary DNA, and polymerase chain reaction products, showed high recovery rates ranging from 95.41% to 99.55%. While these findings highlight the potential of the proposed DNA biosensor as an innovative diagnostic tool for IBV detection, this study remains a proof of concept. However, further validation using a large number of clinical samples is essential to assess its feasibility, robustness, and practical application in a real-world farm setting Full article

Enterococcus faecalis (E. faecalis) is a ubiquitous microbe occurring in the environment and in the intestinal tract of poultry. E. faecalis has been identified in cases of egg infertility and/or decreased hatchability and can cause amyloid arthropathy in older laying chickens. E. faecalis produces cytolysin, a bacterial exotoxin that can cause lysis of erythrocytes. It has been difficult to demonstrate this virulence trait using conventional culture methods with sheep blood agar. A 96-well microplate hemolysis assay, along with a culture method incorporating glucose and L-arginine into the culture media, is described that demonstrates the production of cytolysin in E. faecalis isolates of avian origin. Additionally, the results show that horse and sheep erythrocytes were susceptible to lysis by the E. faecalis cytolysin, but cow and chicken erythrocytes were less susceptible. Full article

Colibacillosis is a chicken disease caused by avian pathogenic Escherichia coli (APEC). Pathogenicity in birds is determined by the occurrence of bacterial genes encoding virulence factors in APEC strains. Furthermore, APEC and other bacterial infections in commercial poultry farms have been treated with intensive use of antimicrobials for decades. Currently, many APEC strains are no longer susceptible to frequently used antibiotics due to increasing antimicrobial resistance (AMR) associated with the acquisition and mutation of other specific bacterial genes. The present study aimed to isolate and detect APEC isolates in broiler farms from different poultry-producing regions of Brazil and to determine their AMR profile. A total of 126 E. coli isolates were obtained from necropsied chickens with colibacillosis. All of these E. coli isolates were analyzed with one species-specific qPCR (targeting uspA gene) and five virulence factors genes qPCRs (targeting iroN, hlyF, iutA, iss, and ompT). AMR was determined by disk diffusion method using ten drugs frequently used to treat colibacillosis in Brazilian poultry farms. The results demonstrated that 109 (86.5%) isolates were classified as APEC. AMR was commonly observed in APEC and AFEC isolates, highlighting resistance for amoxicillin (85; 67.4%) and ceftiofur (72; 57.1%). A total of 41 (32.5%) E. coli isolates presented a multidrug resistance (MDR) profile. These results can contribute to implementing more effective colibacillosis prevention and control programs on Brazilian poultry farms. Full article