Laying Hen Flocks Research Articles

Perch use by laying hens in aviary systems

Perching preference in laying hens is well analysed in several experimental studies. However, information about perch use on farm is scarce. The present study highlights perching preferences at daytime and night-time in 19 laying hen flocks on 18 farms with symmetric (n=9) and asymmetric (n=10) aviary systems. Perch use was higher during night than daytime and perches on high tiers were preferred compared to perches on low tiers. Within the low tier hens preferred the higher perches compared to lowest perches. These findings indicate that in order to fulfil the behavioural priorities of laying hens for perching not only the perch length but also the height of perches within the house should be considered.

The efficacy of flubendazole against different developmental stages of the poultry roundworm Ascaridia galli in laying hens

Infection with the poultry roundworm Ascaridia galli has increased in European countries due to the ban on battery cages. This study was conducted in two commercial laying hen flocks (F1 & F2) on different farms in central Sweden. The aims were to (1) investigate the efficacy of flubendazole (FLBZ, 1.43mg/kg administered in drinking water for 7 days) against adult and larval stages including histotrophic larvae of A. galli, and (2) determine how long it took before the flocks were reinfected after deworming. Accordingly, 180 randomly selected hens were sacrificed before drug administration (bd), on day 3 and 7 during drug administration (dd), and on a weekly basis for up to five weeks post drug administration (pd). Intestinal contents and cloacal materials of each hen plus pooled faecal samples from manure belts were investigated to assess the worm burden and the parasite egg per gram faeces (epg). Additionally, drinking water, and serum and gastrointestinal digesta content samples obtained from ten treated animals were analyzed by HPLC to measure FLBZ and its reduced (R-FLBZ) and hydrolyzed (H-FLBZ) metabolites. No parasite eggs were observed in cloacal samples on day 21 and 28 pd on F1 and on day 21 pd on F2. The epg in manure decreased by 65% and 88% on day 3 dd and by 99% and 97% on day 35 pd on F1 and F2 respectively. Mean FLBZ concentrations quantified in duodenal contents ranged between 0.50 and 0.79μg/g. Although, no histotrophic larvae were found dd, they reappeared one week pd (7±7 F1, 0.5±0.5 F2). Adult worms were found in both flocks before drug administration (44±20 F1, 35±25 F2), on day 3 dd (4±3 F1, 2±2 F2), and then not until day 35 (0.2±0.6) on F1 and day 28 (0.4±0.9) pd on F2. Thus, the only period in which no A. galli were found was on day 7 dd. Although FLBZ was highly efficient our results indicate that the birds were reinfected already within one week pd.

Implications for Welfare, Productivity and Sustainability of the Variation in Reported Levels of Mortality for Laying Hen Flocks Kept in Different Housing Systems: A Meta-Analysis of Ten Studies.

Data from ten sources comprising 3,851 flocks were modelled to identify variation in levels of mortality in laying hens. The predicted increase with age was curvilinear with significant variation between the seven breed categories. Mortality was higher in loose housing systems than in cages and variable within system, confirming previous reports. Cumulative mortality (CM) was higher in flocks with intact beaks (χ2 = 6.03; df 1; p = 0.014) than in those with trimmed beaks. Most data were available for free-range systems (2,823 flocks), where producer recorded CM at 60–80 weeks of age averaged 10% but with a range from 0% to 69.3%. Life cycle assessment showed that the main effect of increased levels of hen mortality is to increase the relative contribution of breeding overheads, so increasing environmental burdens per unit of production. Reducing CM to levels currently achieved by the 1st quartile could reduce flock greenhouse gas emissions by as much as 25%. Concurrently this would enhance hen welfare and better meet the expectation of egg consumers. More research to understand the genetic x environment interaction and detailed records of the causes of mortality is required so that improved genotypes can be developed for different systems and different breeds can be better managed within systems.

Epidemiological aspects of lice (Menacanthus species) infections in laying hen flocks from the State of Minas Gerais, Brazil

The epidemiology of chicken lice species such as Menacanthus stramineus, M. cornutus and M. pallidulus were studied during an observational, analytical and sectional survey, to determine predisposing factors for their occurrence in laying hen farms in the State of Minas Gerais, Brazil. A total of 431 houses on 43 farms were visited in 2012.M. cornutus, M. stramineus and M. pallidulus occurred in 20.9%, 11.6% and 11.6% of farms, respectively. The frequencies of occurrence of M. cornutus, M. stramineus and M.pallidulus in poultry houses were 10.4%, 8.8% and 3.7%, respectively.The epidemiological determinants for the occurrence of these species were investigated using Poisson or logistic regression models.The region of the farm, the recent use of acaricides and the presence of birds, such as saffron finch (Sicalis flaveola), feral pigeon (Columba livia) and Guira cuckoo (Guira guira) around the farms were related to the epidemiology of M. cornutus.Infestation by M. stramineus was associated with age of birds, number of birds per cage and the presence of Guira cuckoo and Chopi blackbird (Gnorimopsar chopi) near the poultry houses.The occurrence of M. pallidulus was influenced by the type of facilities, presence of cattle egret (Bubulcus ibis) and free-range domestic hens around the farm.The use of wire mesh nets in the houses and of forced moulting did not influence lice infestation.

The prevalence of Salmonella infections in laying hen flocks producing eggs and their impact on the public health

Since 2008, Slovakia has implemented the National control program of Salmonella infections in laying hen flocks. This program requires the farm operators to monitor and investigate the invasive types of Salmonella (S. Enteritidis and S. Typhimurium) according to STN ISO 6579. The aim of this study was to perform a microbiological examination of dust and chicken droppings samples of laying hens in the Trenčín region for the presence of Salmonella by Horizontal method according to STN ISO 6579: 2002, to compare results with the statistics across Slovakia and selected EU countries and to evaluate the impact of official controls of salmonellosis in animals and humans. In the years 2009 - 2013 in the Trenčín region, 730 samples of dust from the conveyor belts and droppings of laying hens were taken to determine the prevalence of Salmonella in individual rearings. In these years, the incidence of positive samples was found from 0% to 29.17%. For the period from 2009 till 2013 was reported 22833 salmonellosis cases in human population of Slovakia, while in the Trenčín region it was 2636. Five-year EU-trend (2009 - 2013) showed a statistically significant decrease of salmonellosis occurence (with a mean reduction of 12% per year). The Wilcoxon signed-rank test was performed in order to provide in-depth epidemiological assessment of salmonellosis cases in Trenčin region in relation to selected characters: etiological agens, transmission mechanism, age, location as well as seasonality of infection.

Isolation of a novel thermophilic Campylobacter from cases of spotty liver disease in laying hens and experimental reproduction of infection and microscopic pathology

The condition known as spotty liver disease or spotty liver syndrome can cause significant mortality in free range laying hen flocks. It has been described in Europe and Australia but the aetiology has not been established. There are similarities between spotty liver disease and avian vibrionic hepatitis, a condition which was reported in the 1950s. A Vibrio-like organism was suspected to be the cause of avian vibrionic hepatitis, although this organism was never fully characterised.We report the isolation of a novel Campylobacter from five separate outbreaks of spotty liver disease. The conditions required for culture, the growth characteristics, electron microscopical morphology and results of the phenotypic tests used in the identification of this novel Campylobacter sp. are described. The novel Campylobacter is slow growing and fastidious and does not grow on media routinely used for isolating Campylobacter sp. The morphology is typical for a Campylobacter sp. and phenotypic tests and a duplex real time PCR test differentiate the novel Campylobacter from other members of the genus. 16S rRNA analysis of 19 isolates showed an identical sequence which appears to represent a hitherto unknown sub lineage within the genus Campylobacter. Experimental intraperitoneal infection of four week old SPF chickens produced microscopic liver pathology indistinguishable from natural disease and the novel Campylobacter was recovered from the experimentally infected chicks. The isolates described appear to be a possible causal organism for spotty liver disease.

Risk Factors Associated With Salmonella in Laying Hen Farms: Systematic Review of Observational Studies.

Salmonella contamination of laying hen flocks and shell eggs is associated with various management and environmental factors. Foodborne outbreaks of human salmonellosis have been traced back to consumption of Salmonella-contaminated shell eggs. In the present study, a systematic literature review was conducted to identify and provide an evidence-based overview of potential risk factors of Salmonella contamination of laying hens, layer premises, and shell eggs. This systematic literature search was conducted using AGRICOLA, CAB Abstracts, and PubMed databases. Observational studies that identified risk factors for Salmonella contamination of layer flocks and shell eggs were selected, and best evidence was synthesized to summarize the results. Altogether, 13 cross-sectional studies and four longitudinal studies published in English were included in the review. Evidence scores were assigned based on the study design and quality of the study to grade the evidence level. The strength of association of a risk factor was determined according to the odds ratios. In this systematic review, the presence of previous Salmonella infection, absence of cleaning and disinfection, presence of rodents, induced molting, larger flock size (>30,000 hens), multiage management, cage housing systems, in-line egg processing, rearing pullets on the floor, pests with access to feed prior to movement to the feed trough, visitors allowed in the layer houses, and trucks near farms and air inlets were identified as the risk factors associated with Salmonella contamination of laying hen premises, whereas high level of manure contamination, middle and late phase of production, high degree of egg-handling equipment contamination, flock size of >30,000, and egg production rate of >96% were identified as the risk factors associated with Salmonella contamination of shell eggs. These risk factors demonstrated strong to moderate evidence of association with Salmonella contamination of laying hens and shell eggs. Eggshells testing positive for Salmonella were 59 times higher when fecal samples were positive and nine times higher when floor dust samples were positive. Risk factors associated with Salmonella Enteritidis infection in laying hens were flock size, housing system, and farms with hens of different ages. As a summary, this systematic review demonstrated that Salmonella contamination of laying hen flocks and shell eggs in layer production systems is multifactorial. This study provides a knowledge base for the implementation of targeted intervention strategies to control Salmonella contamination of laying hen flocks and shell eggs.

Potential Transmission Pathways of Streptococcus gallolyticus subsp. gallolyticus.

Streptococcus gallolyticus subsp. gallolyticus (S. gallolyticus subsp. gallolyticus), a member of group D streptococci, is an inhabitant of the animal and human gastrointestinal tract. Furthermore, it is a facultative pathogen which causes e.g. endocarditis, septicemia and mastitis. S. gallolyticus subsp. gallolyticus may be transmitted either directly or indirectly between animals and humans. However, the transmission routes are an unsolved issue. In this study, we present systematic analyses of an S. gallolyticus subsp. gallolyticus isolate of an infective endocarditis patient in relation to isolates of his laying hen flock. Isolates from pooled droppings of laying hens, pooled dust samples and human blood culture were characterized by using multilocus sequence typing (MLST) and DNA fingerprinting. MLST revealed the same allelic profile of isolates from the human blood culture and from the droppings of laying hens. In addition, these isolates showed clonal identity regarding a similar DNA fingerprinting pattern. For the first time, we received a hint that transmission of S. gallolyticus subsp. gallolyticus between poultry and humans may occur. This raises the question about the zoonotic potential of isolates from poultry and should be considered in future studies.

Clostridial co-infection episodes in commercial laying hens

The present report describes two outbreaks of serious enteritis in commercial laying hens where Clostridium perfringens and Clostridium colinum were simultaneously detected. At the age of 44 and 31 weeks, two laying hen flocks showed an increase of the mortality rate and a worsening of productive performance. Post-mortem examination revealed intestinal necrotic-haemorrhagic ulcerations and hepatic focal necrosis. The bacteriological examination yielded the isolation of C. colinum and C. perfringens toxin type A, NetB positive. In one outbreak, C. colinum was detected also by polymerase chain reaction in all the intestines of affected birds. In laying hens, C. colinum has never been isolated but only suspected as the causative agent of a slight enteric disease called duodenal focal necrosis. The present case report was characterized by severe enteritis presumably due to the synergistic effect of C. colinum and C. perfringens.

Intestinal colonization of different Brachyspira spp. in laying hens

BACKGROUND:Avian intestinal spirochetosis (AIS) is causedby spiral-shaped Gram-negative Brachyspira spp. in poultry. It isknown as a cause of diarrhea, low egg production, and increasedoccurrence of dirty eggs in layer hens. OBJECTIVES: In this study,the presence of some Brachyspira spp. was investigated in layinghens. METHODS: A total of 100 cloacal swab samples wereindividually collected from 20 laying hen flocks showing fecal eggstaining in northeast of Iran. RESULTS: Using culture andmorphologic examination, 41 samples (41%) from 20 flocks werepositive; however, by using genus-specific PCR, only 37 (37%)samples were confirmed as Brachyspira spp. Using speciesspecificprimers, single colonization was identified in 18 samplesassociated with B. pilosicoli (48.6%), while single colonizationwith B. intermedia was found in only two samples (5.4%).Simultaneous colonization by B. intermedia and B. murdochii wasdetected in 3 samples (8.1%). B. pilosicoli was the most prevalentspecies in concurrent colonization in 11 cases (29.7%). Finally, cocolonizationby B. intermedia and B. innocens was identified in 3samples (8.1%). CONCLUSIONS: The results of this study showedthe colonization of different species of Brachyspira withdominance of B. pilosicoli in layer hens.

Salmonella serovars in laying hen flocks and commercial table eggs from a region of São Paulo state, Brazil

Salmonella spp. is the main originator of human foodborne diseases worldwide and is mainly transmitted by food containing eggs. In Brazil, as a result of the lack of studies and data collection very little is known about the prevalence of Salmonella spp. in laying hen flocks and commercial table eggs. Consequently the present study was elaborated and aimed at generating data about Salmonella spp. in part of the Brazilian egg production chain. Eight flocks of day-old chicks, eight flocks of adult laying hens (four vaccinated with bacterin against Salmonella Enteritidis and four unvaccinated) and commercial table eggs from four supermarkets were examined. Salmonella spp. was isolated in 50 % of the newly hatched chicks, 25 % of the adult flocks and 1.5 % of egg samples examined. S. enterica subsp. enterica 4,12:r:-, S. Mbandaka, S. enterica subsp. enterica 6,7: z10:-, S. Enteritidis and S. Havana were the serovars isolated in birds. In commercial table-eggs S. Mbandaka, S. enterica subsp. enterica 6,7: z10:- and S. Braenderup were isolated. These results show that Salmonella spp. is present in laying hen flocks and consequently in eggs destined for human consumption. Probably, some of the Salmonella serovars are being introduced in egg farms by vertical via.

Erysipelothrix rhusiopathiae contamination in the poultry house environment during erysipelas outbreaks in organic laying hen flocks

This study investigated organic laying hen farms for the presence of Erysipelothrix rhusiopathiae in the house environment and from potential carriers (i.e. insects and mice) during ongoing erysipelas outbreaks, and compared the obtained isolates with those from laying hens. The samples were investigated by selective culture followed by species-specific polymerase chain reaction on cultures. E. rhusiopathiae was isolated from the spleen, jejunal contents, manure, dust and swabs from water nipples. Three more samples from the house environment tested positive by polymerase chain reaction compared with selective culture alone. Selected isolates were investigated by pulsed-field gel electrophoresis (PFGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). One farm was represented by isolates from laying hens only, and one of these isolates differed in one PFGE band from the others. Different banding patterns were observed for isolates from laying hens and manure on one farm. On the remaining two farms, the isolates from the house environment and laying hens were identical but differed between farms. Outbreaks reoccurred in the next flock on two of the farms, and different PFGE types were isolated from consecutive flocks. Our results suggest an external source of infection, which would explain the previously reported increased risk of outbreaks in free-range flocks. Contaminated manure and dust may represent sources of transmission. For the isolates, MALDI-TOF MS and biochemical typing results were in agreement but, since the type strain of Erysipelothrix tonsillarum was typed as E. rhusiopathiae using MALDI-TOF MS, further studies into this method are needed.

Use of outdoor ranges by laying hens in different sized flocks

In studies assessing outdoor range use of laying hens, the number of hens seen on outdoor ranges is inversely correlated to flock size. The aim of this study was to assess individual ranging behavior on a covered (veranda) and an uncovered outdoor run (free-range) in laying hen flocks varying in size. Five to ten percent of hens (aged 9–15 months) within 4 small (2–2500 hens), 4 medium (5–6000), and 4 large (≥9000) commercial flocks were fitted with radio frequency identification (RFID) tags. Antennas were placed at both sides of all popholes between the house and the veranda and the veranda and the free-range. Ranging behavior was directly monitored for approximately three weeks in combination with hourly photographs of the free-range for the distribution of hens and 6h long video recordings on two parts of the free-range during two days. Between 79 and 99% of the tagged hens were registered on the veranda at least once and between 47 and 90% were registered on the free-range at least once. There was no association between the percentage of hens registered outside the house (veranda or free-range) and flock size. However, individual hens in small and medium sized flocks visited the areas outside the house more frequently and spent more time there than hens from large flocks. Foraging behavior on the free-range was shown more frequently and for a longer duration by hens from small and medium sized flocks than by hens from large flocks. This difference in ranging behavior could account for the negative relationship between flock size and the number of hens seen outside at one point of time. In conclusion, our work describes individual birds’ use of areas outside the house within large scale commercial egg production.

Mixed infection by fowlpox virus and Chlamydophila psittaci in a commercial laying hen flock

An outbreak of fowlpox occurred in a commercial laying hen flock in one of the western provinces of Poland. Clinical signs suggested fowlpox and the diagnosis was confirmed by histopathological detection of Bollinger bodies within the epithelial cells. Detailed ultrastructural examination revealed an additional concurrent infection with chlamydia-like particles. The particles were identified by PCR as fowlpox virus and Chlamydophila psittaci. It is worth noting that both pathogens can generate morphologic forms capable of prolonged survival and inducing latent and persistent infection. We suggest a possible interaction between the two pathogens on ultrastructural level and assess the clinical consequences of the mixed infection. This study also demonstrates a potential of the transmission electron microscope (TEM) for identifying a superinfection with another pathogen (in this case C. psittaci), which may remain undetected by routine techniques.

Higher precision level at individual laying performance tests in noncage housing systems

With the Weihenstephan funnel nest box, 12 laying hen flocks were tested for their individual laying performance, egg quality, and nesting behavior in a noncage environment. During the whole observation period of 8 yr, a transponder-based data recording system was continuously improved and resulted in a recording accuracy of 97%. At peak production, heritabilities for the number of eggs laid are in some flocks higher than expected. With improved data accuracy, heritability estimates on individual egg weights are more stable. Heritabilities for nesting behavior traits range between a low to moderate level, providing very useful information for laying hen selection to help improve traits that cannot be recorded in cages. Over the years, the benefits of the Weihenstephan funnel nest box for laying hen breeders have grown. This is due to higher data recording accuracies and extended testing capacities, which result in more reliable genetic parameters.

Effect of a reduced crude protein, amino acid-balanced diet on hen performance, production costs, and ammonia emissions in a commercial laying hen flock

SUMMARY This investigation sought to determine if reduced CP, amino acid (AA) balanced laying hen diets could maintain egg production and quality while reducing feed costs or increasing farm revenue under commercial-scale conditions. A total of 50,760 Lohmann LSL Lite laying hens were divided into 3 groups that were each fed least-cost formulated corn-soybean meal-based diets from 18 to 51 wk of age. Diets contained low, intermediate, or high (control) levels of CP and were supplemented with limiting AA. Monthly replicated data collection included feed nutrient and particle size analyses, hen BW, egg quality analyses, and manure nutrient and NH3 flux measurements for each dietary treatment. Weekly nonreplicated data collection by the producer included egg production and grade-out data and feed cost and egg income reports. Hen BW, egg weight, and egg quality (replicated data) did not differ significantly by level of dietary CP (P > 0.05). Egg production (nonreplicated data) was similar across all diets. Manure nutrients and NH3 flux also did not differ by dietary treatment. Overall, the low and intermediate CP diets were less costly and resulted in greater revenue compared with the high CP (control) diet. Therefore, implementing reduced CP, AA-balanced diets for commercial-scale laying hen flocks would be economically beneficial without sacrificing hen performance.

AnAvian Coronavirusin Quail with Respiratory and Reproductive Signs

An Avian coronavirus was detected in pools of lungs, tracheas, female reproductive tracts, kidneys, and enteric contents from quail (Coturnix coturnix japonica) and laying hen flocks, with and without infectious bronchitis (IB)-like signs, cohoused in farms located in two states of southeastern Brazil during 2009-2010. Although Avian metapneumovirus subtype B was found in two layers samples, Newcastle disease virus was not found in quail or in hens. Based on DNA sequences for the 3'-untranslated region and the gene encoding the RNA-dependent RNA polymerase, this avian coronaviruses in quail is an IB virus-like gammacoronavirus.

In vitro sensitivity of poultry Brachyspira intermedia isolates to essential oil components and in vivo reduction of Brachyspira intermedia in rearing pullets with cinnamaldehyde feed supplementation

Cecal enteritis due to Brachyspira infections tends to be chronic in laying hens. Limited availability of antimicrobial drugs for use in laying hens emphasizes the need for alternative control measures. A broth microdilution method was used to determine the antimicrobial susceptibility of 20 Brachyspira intermedia field isolates from laying hen flocks to components of essential oils (EO). Minimal inhibitory concentration (MIC) distributions, obtained for 8 EO components, were all monomodal. Cinnamaldehyde had the lowest MIC values (40 to 80 mg/L), followed by nerolidol, capsaicin, carvacrol, and thymol (80 to 320 mg/L), eugenol (160 to 640 mg/L), and linalool (320 to 1,280 mg/L). The MIC ranges of piperine were mostly above the test range of 1,280 mg/L. In an in vivo experiment, coated trans-cinnamaldehyde was supplemented to the feed of rearing pullets. A completely randomized experimental design with 4 treatments and 3 replicates each (replicate = group of seven 1-d-old laying hen chickens) was applied. The negative and positive controls received a conventional feed during the whole trial. The positive controls were orally inoculated on 3 consecutive days (d 22, 23, and 24) with 1 mL of 1.0 × 108 cfu/mL of a B. intermedia field isolate. Two treatment groups (preventive and curative), identically inoculated, received the coated trans-cinnamaldehyde-supplemented feed (500 mg/kg of trans-cinnamaldehyde), the preventive group from d 1, the curative from d 25. On d 32, ceca were collected for bacteriologic Brachyspira enumeration. The mean enumeration of Brachyspira cells was decreased (P < 0.05) in the curative treated group versus the positive control group. The in vitro results of the present study demonstrate the potential of EO components as antimicrobials against poultry Brachyspira isolates, including isolates with acquired resistance for classic antimicrobial drugs. Reduction of Brachyspira colonization in young pullets was obtained, in a curative way, in an in vivo study using feed supplemented with coated trans-cinnamaldehyde. Further studies are necessary to investigate the mode of action of the coated trans-cinnamaldehyde in reducing Brachyspira colonization of the ceca.

Erysipelas in laying hens is associated with housing system

Following the change from conventional cages to non-cage housing systems and furnished cages, which in Sweden was finalised by 2005, problems caused by Erysipelothrix rhusiopathiae increased in laying hen flocks....

Detection of a new Non-Classified Chlamydia Species in Hens in Poland

Abstract The outbreak of chlamydiosis in one of the western provinces of Poland, was diagnosed accidentally as a concurrent infection in a commercial laying hen flock during an outbreak of fowl pox. For histological examination, skin and subcutaneous tissue samples from lesions on heads of the birds were collected. Swabs from throat and trachea have been examined by nested PCR, real-time PCR, and partial ompA sequencing. Detailed electron microscopy analysis revealed fowl pox intracytoplasmic inclusions, called Bollinger bodies, and the presence of other intracytoplasmic inclusions; specific for Chlamydia sp. Results of nested PCR confirmed the presence of Chlamydiaceae sp. in two tested samples. Surprisingly, one of the two Chlamydiaceae-positive cases turned out to be infected with a non-classified strain. Results of real-time PCR and sequencing confirmed the presence of a new Chlamydia species that has not been found in Poland to date. Partial sequencing and BLAST analysis of ompA gene sequence confirmed the highest homology to non-classified poultry strains of Chlamydia sp. that were previously detected in Germany and France. The zoonotic potential and the exact taxonomic status of this atypical strain have yet to be defined.