Characterising Free-Range Layer Flocks Using Unsupervised Cluster Analysis

Simple Summary: Little is known on how free-range laying hens on commercial farms exploit their offered resources. However, only when hen usage of the structural resources is understood, can design improvements be made to optimize hen health and welfare. This study was conducted in order to understand the extent to which free-range hens use the aviary system and range. With the help of individual tracking technology, agglomerative, and K-means cluster analysis, we were able to characterize various flock sub-populations. Regardless of the cluster group, hens used the nest boxes and lower feeder tier more consistently compared to the outdoor range and the upper feeder tier. Overall, hens that were more consistent with their average time spent at each location stayed for longer duration at each location than those hens that had inconsistent movement patterns. The identification of 'routine' behavior patterns can be essential for flock management, such as smothering prevention and future shed design. Abstract: This study aimed to identify sub-populations of free-range laying hens and describe the pattern of their resource usage, which can affect hen performance and welfare. In three commercial flocks, 3125 Lohmann Brown hens were equipped with radio-frequency identification (RFID) transponder leg bands and placed with their flock companions, resulting in a total of 40,000 hens/flock. Hens were monitored for their use of the aviary system, including feeder lines, nest boxes, and the outdoor range. K-means and agglomerative cluster analysis, optimized with the Calinski-Harabasz Criterion, was performed and identified three clusters. Individual variation in time duration was observed in all the clusters with the highest individual differences observed on the upper feeder (140 ± 1.02%) and the range (176 ± 1.03%). Hens of cluster 1 spent the least amount time on the range and the most time on the feed chain located at the upper aviary tier (

Managing Free-Range Laying Hens-Part A: Frequent and Non-Frequent Range Users Differ in Laying Performance but Not Egg Quality

Little is known about the impact of ranging on laying performance and egg quality of free-range hens. The aim of this study was to characterise egg production of commercial free-range laying hen sub-populations of low-, moderate- and high-range use at an early age. A total of five flocks with 40,000 hens/flock were investigated where 1875 hens/flock were randomly selected at 16 weeks of age, monitored for their range use and subsequently grouped into "stayers" (the 20% of hens that spent the least time on the range), "roamers" (the 20% of the hens that used the range more than stayers but less than rangers) and "rangers" (the 60% of the hens that spent the most time on the range). Eggs from the individual groups were collected in 10-weekly intervals until hens were 72 weeks of age, commercially graded and tested for several quality parameters. Significant differences were noted for hen-day production. For example, at 22 weeks of age, rangers enjoyed a laying rate of 88.0% ± 1.1%, while stayers performed at 78.2% ± 1.9% but at 72 weeks of age egg production of rangers was 85.1% ± 0.9% and of stayers was 95.5% ± 0.9% (

Body weight and range usage affect net energy utilisation in commercial free-range laying hens when evaluated in net energy chambers

Within a given free-range flock, some hens prefer to spend the majority of their time in the shed (stayers), while others frequently access the range (rangers). Laying performance has been associated not only with the development of these sub-populations but also with different body weights (BW). The purpose of this study was to determine if range usage, BW or a combination of both is associated with energy metabolism and as such contribute to improved hen performance. Forty-eight Lohmann Brown hens at 74 wk of age were selected from a commercial free-range farm based on their BW and range usage over a 56-week period. Using a 2 × 2 factorial arrangement, hens were either classified as heavy (mean ± SEM; 2.01 ± 0.02 kg, n = 24) or light (1.68 ± 0.01 kg, n = 24), and also classified as rangers (accessed the range for 84.1% of available days, 242 ± 3.75 d; n = 24) or stayers (accessed the range for 7.17% of available days; 23.4 ± 6.08 d, n = 24). Stayers had significantly higher metabolizable energy (ME) intake per metabolic BW per d (0.852 vs. 0.798 MJ/kg BW0.75 per d; P = 0.025), higher heat production (0.637 vs. 0.607 MJ/kg BW0.75 per d; P = 0.005), higher heat increment (0.267 vs. 0.237 MJ/kg BW0.75 per d; P = 0.005) and retained more nitrogen (1.59 vs. 1.46 g/hen per d; P = 0.023) compared to the rangers. Light hens had significantly higher metabolic energy intake per metabolic BW (0.854 vs. 0.796 MJ/kg BW0.75 per d; P = 0.018), net energy (NE) intake (0.595 vs. 0.551 MJ/kg BW0.75 per d; P = 0.032), and retained energy (0.225 vs. 0.181 MJ/kg BW0.75 per d; P = 0.032), as well as lower heat production (0.936 vs. 1.003 MJ/hen per d; P = 0.002) compared to heavier hens. An interaction was observed across levels of analysis i.e. between light stayers and light rangers. The light rangers had significantly higher NE intake compared to the light stayers (9.77 vs. 9.27 MJ/kg BW0.75 per d; P = 0.024). In conclusion, light hens were more energy efficient compared to heavy hens. Moreover, light rangers had a more efficient feed utilisation compared to the light stayers

Effect of pecking stones and age on feather cover, hen mortality, and performance in free-range laying hens

Severe feather pecking is frequently associated with impaired egg production, poor hen welfare, and increased mortality. The aim of this study was to investigate the potential of pecking stones to ameliorate the incidence of feather pecking. A total of 18 flocks of Hy-Line Brown laying hens were randomly assigned to control (n = 9 no pecking stone access) or treatment (n = 9 pecking stone access) flocks and housed in commercial fixed sheds (farm A, n = 10) or commercial mobile sheds (farm B, n = 8) differing in various housing conditions. Beak length, feather score, egg production, and mortality were evaluated at 16 wk of age and every 10 wk until at least 46 wk of age. On farm A, hens with access to pecking stones had significantly lower mortality than hens without pecking stone access (P = 0.001). A significant interaction between pecking stone and age was observed on feather scores of wings of hens housed in farm A. Hens of the pecking stone group in farm A had higher wing feather score (indicating better feather condition) at the age of 56 and 66 wk than hens with no access to pecking stones (pecking stone × age, P = 0.002). The age of the hens was significantly associated with lower overall feather scores (poorer feather condition), reduced egg production, and higher mortality (P,0.05). Although pecking stones reduced some feather loss and mortality, this effect was only present on one farm and therefore may be related to farm management. Especially the impact of pecking stones on mortality was inconclusive as the cumulative mortality in farm B was nearly twice as high compared with that in control flocks. Further investigations are warranted including the effects of pecking stone provision at an early age such as during rearing (0–17 wk of age)

Frequent Visits to an Outdoor Range and Lower Areas of an Aviary System Is Related to Curiosity in Commercial Free-Range Laying Hens

Individual hen preferences to spend time at particular locations within a free-range aviary system and relationships with temperament is relatively unknown. Hens (n = 769) from three commercial flocks were monitored with Radio Frequency Identification technology to determine time spent on the range, upper and lower aviary tiers, and nest boxes. Prior depopulation, novel arena (NA) and novel object (NO) tests assessed exploration and fearfulness. During early life; more time on the lower tier was associated with more lines crossed in the NA test (p p = 0.0001). Over the hens' whole life; time spent on range and lower tier was associated with approaching the NO (p

Technological Quality, Amino Acid and Fatty Acid Profile of Broiler Meat Enhanced by Dietary Inclusion of Black Soldier Fly Larvae

We evaluated the effects of full-fat black soldier fly larvae (BSFL) on broiler carcass composition, cut yield, and breast meat quality. Broilers were fed for 42 days with up to 20% dietary inclusion of BSFL (0, 5, 10, 15, and 20%). On day 42, 120 broilers were slaughtered, and images were taken using computed tomography. Breasts, drumsticks, and thighs were collected for cut yield determination. The pH, color, lipid oxidation, cooking loss, shear force, amino acid profile, and fatty acid profile of the breast meat were assessed. There was no dietary effect on carcass composition or meat quality parameters except for fatty and amino acids compositions. When 20% BSFL was included in the diet, individual fatty and amino acids, such as lauric and myristic acids, aspartic acid, glutamine, and lysine, increased by 22.0-, 5.50-, 1.08-, 1.06-, and 1.06-fold, respectively (

Production Systems Related to Free Range Management of Laying Hens

In Australia, free-range housing of laying hens enjoys a large variety of production systems. Hens may be housed on litter floors, slats, an aviary system, or a combination of the above. The outdoor environment may be managed using fixed ranges, rotational ranges, or portable sheds (Ruhnke et al., 2015). Each production system has different impacts on layer health, welfare, and performance. Matching the rearing with the housing system, modifications of the hen house, and environmental enrichment can significantly reduce the stress level of the individual hen (El-Lethey et al., 2000)

Free-range egg production in Australia: industry trends and challenges

In Australia, free-range egg production is a rapidly growing sector with an estimated grocery market value share of 48% of total table egg production. It can be estimated that around 200 commercial free-range egg producers are currently active. This report reflects the current situation these farmers are facing. Adverse climate conditions and Avian Influenza are a concurrent threat to the freerange egg industry. However, on-range feeding is a common feed strategy performed by up to 47.5% of free-range egg producers. With six states and two territories, no national regulations regarding free range hen housing and egg production are in place. In general, two housing systems can be distinguished: fixed housing and mobile housing. The use of guard animals to protect hens from predators is common. The large variety of farming systems and management procedures is reflected in the variety of challenges free-range hens are facing. In a recent survey, free-range layer producers attributed their losses to predation (42%), heat stress (37%), cannibalism (37%), grass impaction (21%), diseases (21%), and malnutrition (5%). Furthermore, internal and external parasites can be considered as widely prevalent. Producers identified that research should be conducted in welfare (52%), pasture management (54%), nutrition (44%), bird health (44%), housing (40%), and economics (29%). With those demands currently under investigation, Australia can be considered as highly active in the field of applied research focusing on free range-egg production

Studien über den Einfluss von organischen Säuren sowie der Futterverarbeitung auf verdauungsphysiologische Parameter bei Broilern und Legehennen

The intestinal tract of chickens is characterized by efficient nutrient digestion. Disturbances of this fragile system results frequently in reduced animal health and welfare and subsequently increased use of antibiotics. Feed additives and various feed processing technologies can be used in order to affect intestinal function of the chicken. The goal of this study was to study the impact of acidification and thermal treatment of feed, the use of various feed particle sizes, and the impact of milling methods on intestinal physiology of poultry. The aims of this thesis were: I) to adapt the Ussing chamber method for reliable assessment of transport physiology of the intestinal mucosa of poultry, II) to evaluate the impact of acidified feed on apparent ileal digestibility of starch, the glucose transporter expression, and intestinal transport function in broiler chickens, III) to investigate the impact of the milling method, thermal treatment and particle size of feed on performance, apparent ileal nutrient digestibility, and pH of digesta in laying hens. Part I was performed by stripping the tunica mucosa from a total of 104 jejunal samples from 10 hens and using a net device for stabilizing support. In order to investigate the benefit of glutamine, 50 samples were maintained with a conventional buffer (group 1), and 54 samples were maintained with additional 5 mM glutamine (group 2). Mean short circuit current (ΔIsc) of samples exposed to 10 mM glucose in group 1 and group 2 was 17.0 ±2.47 μA/cm2 and 14.6 ±1.54 μA/cm2 (p = 0.836), of samples exposed to 100 μM phloridzin -13.3 ±1.63 μA/cm2, and -11.8 ±1.22 μA/cm2 (p = 0.712) and of samples exposed to 100 μM carbachol 4.7 ±0.70 μA/cm2, and 3.7 ±0.43 μA/cm2 (p = 0.450), respectively. While glutamine had no beneficial effect on tissue response, the method described here allowed for reliable investigation of the intestine. Part II of this thesis was performed by feeding broilers a standard diet without or with 1.5 % Lupro-Cid® (64 % formic acid, 25 % propionic acid, 11 % water) for 32-35 days. Apparent ileal starch digestibility was determined using 0.2 % titanium dioxide as indigestible marker. Intestinal transporter function was analyzed in Ussing chamber experiments where jejunal samples were sequentially exposed to 10 mM glucose, 100 μM phloridzin, 100 μM histamine, and 100 μM carbachol. Additionally, gene expressions of SGLT-1 and GLUT-2 transporters were analyzed using qPCR analysis. Apparent ileal starch digestibility of the control group (97.5 ±0.35 %) and the acid-treated group (97.0 ±0.59 %) did not differ significantly (p = 0.674). Tissue conductance of intestinal samples obtained from the control group and the acidtreated group was 10.6 ±0.68 mS/cm2, and 9.4 ±0.80 mS/cm2, respectively (p = 0.147). The mean short circuit currents (ΔIsc) of the samples exposed to glucose, phloridzin, histamine, and carbachol did not differ (p = 0.209, p = 0.296, p= 0.498, and p = 0.640, respectively). Additionally, no differences in the expression of SGLT-1 and GLUT-2 could be observed (p = 0.942, p = 0.431). Part III of this thesis was performed using twelve variants of a complete diet that were produced by four different milling techniques including hammer mill, roller mill, disc mill, and a wedge-shaped disc mill. Coarse feed particles were obtained from all mills, additional fine feed particles were obtained from the hammer mill and the roller mill. Each of this six feed variants was offered as mash or expandate, resulting in twelve treatments in total. Laying hens at 20 weeks of age were kept for three weeks in eight replicates with six hens per feeding group. Performance parameters (feed consumption, laying performance, feed conversion ratio) and apparent ileal digestibility of crude protein, amino acids, ether extract, and starch were determined. The pH of the digesta was determined along the gastrointestinal tract. In week 1 and 2 of the experiment, feed intake was significantly increased in hens fed with mash feed compared to hens fed expanded feed (p = 0.003 and p = 0.023). The apparent ileal digestibility of starch was improved (p < 0.001) by feeding mash and correlated positively to increased particle size (p-linear = 0.001; p-quadratic = 0.006; r = 0.363). The apparent ileal digestibility of ether extract correlated negatively to increased particle sizes (p-linear = 0.003; p-quadratic = 0.225; r = -0.311). The pH of the ileum content (p-linear = 0.044; p-quadratic = 0.146; r = 0.212) and feces (p-linear = 0.010; p-quadratic = 0.016; r = 0.267) correlated with increased particle sizes. Based on the results of this thesis, organic acids had no impact on ileal starch digestibility and intestinal nutrient uptake. Therefore, the investigation of the mode of action needs further studies. Feeding coarse particle sizes improved ileal starch digestibility. Unconventional, energy saving milling methods enabling coarse particle sizes of feed may be used without negative impact on laying performance and the digestive function of laying hens.Der Verdauungstrakt des Geflügels zeichnet sich durch eine effiziente Nährstoffnutzung aus. Durch Störungen kommt es zu unerwünschten Konsequenzen für die Tiergesundheit und das Wohlbefinden, sie können den Einsatz von Antibiotika erforderlich machen. Futteradditive und technologische Verfahren können Einfluss auf den Gesundheitsstatus von Hühnern nehmen. In vorliegender Dissertation sollte die Verwendung von organischen Säuren, der Hitzebehandlung des Futters, die Darreichung verschiedener Futterpartikelgrößen, sowie der Einsatz von verschiedenen Mahlmethoden zur Futterherstellung untersucht werden. Der Einfluss dieser Maßnahmen auf die Physiologie des Magen-Darm- Traktes des Geflügels ist bisher nicht umfassend untersucht worden. Das Ziel dieser Arbeit war daher: I) die Ussingkammermethode zur Charakterisierung von Absorptions- und Sekretionsprozessen im Geflügeldarm zu verbessern, II) den Einfluss von organischen Säuren als Futteradditive auf die ileale Stärkeverdaulichkeit, die intestinale Expression von Glukosetransportern sowie die jejunale Transport- und Barrierefunktion zu erfassen, III) die Bedeutung verschiedener Mahlmethoden, der Hitzebehandlung des Futters sowie der Futterpartikelgröße auf die Leistung, die scheinbare ileale Nährstoffverdaulichkeit und den pH der Digesta bei Legehennen zu bestimmen. Teil I der Fragestellung wurde durchgeführt, indem die Tunica Mucosa von insgesamt 104 Jejunumproben aus 10 Legehennen mit einem Netz stabilisiert und in die Ussingkammer verbracht wurden. Während 50 Proben mit einem konventionellen Puffer behandelt wurden (Gruppe 1), wurde 54 Proben zusätzlich 5 mM Glutamin zugesetzt (Gruppe 2). Nach Zugabe von 10 mM Glukose betrug die durchschnittliche Höhe des Kurzschlussstromes (ΔIsc) der Gruppe 1 17,0 ±2,47 μA/cm2 und der Gruppe 2 14,6 ±1,54 μA/cm2 (p = 0,836). Nach Zugabe von 100 μM Phloridzin betrug der ΔIsc -13,3 ±1,63 μA/cm2 bzw. -11,8 ±1,22 μA/cm2 (p = 0,712), nach Zugabe von 100 μM Carbachol 4,7 ±0,70 μA/cm2 bzw. 3,7 ±0,43 μA/cm2 (p = 0,450). Teil II der Dissertation wurde durchgeführt, indem Masthähnchen einer Kontrollgruppe mit Masthähnchen einer Versuchsgruppe verglichen wurden. Die Tiere der Versuchsgruppe hatten während der gesamten Aufzucht von 32-35 Tagen 1,5 % Lupro-Cid® (64 % Ameisensäure, 25 % Propionsäure, 11 % Wasser) über das Futter aufgenommen. Die ileale Stärkeverdaulichkeit wurde mittels 0,2 % Titandioxid ermittelt. Die jejunale transmembranale Transporterfunktion wurde mittels Ussingkammermethode bestimmt, indem die Darmproben nacheinander mit 10 mM Glukose, 100 μM Phloridzin, 100 μM Histamin und 100 μM Carbachol behandelt wurden. Zusätzlich wurde die Genexpression der Glukosetransporter SGLT-1 und GLUT-2 mittels qPCR- Analyse bestimmt. Die scheinbare ileale Stärkeverdaulichkeit der Kontrollgruppe betrug (97,5 ±0,35 %), die der Säuregruppe (96,0 ±0,59 %). Der Unterschied war statistisch nicht signifikant (p = 0,674). Die mittlere (±SEM) Leitfähigkeit des Gewebes betrug für die Kontroll- und Säuregruppe 10,6 ±0,68 mS/cm2, bzw. 9,4 ±0,80 mS/cm2 (p = 0,147). Die mittleren Kurzschlussströme (ΔIsc) der Gruppen nach Behandlung mit Glucose, Phloridzin, Histamin und Carbachol waren statistisch nicht signifikant unterschiedlich (p = 0,209, p = 0,296, p = 0,498 und p = 0,640). Weiterhin konnten keine Unterschiede in der relativen Genexpression der SGLT-1 und GLUT-2 Transporter nachgewiesen werden (p = 0,942, p = 0,431). Teil III der Dissertation wurde ausgeführt, indem zwölf Varianten derselben Futterrezeptur mit vier Mahlmethoden (Hammermühle, Walzenstuhl, Scheibenmühle, Keilscheibenzerkleinerer) hergestellt wurden. Die Mühlen wurden so eingesetzt, dass relativ grobe Partikelgrößen hergestellt wurden. Zusätzlich wurden mittels Hammermühle und Walzenstuhl feine Futterpartikel gefertigt. Jede der sechs Varianten wurde entweder als Mehl oder als Expandat verfüttert, wodurch insgesamt 12 Versuchsgruppen entstanden. Legehennen im Alter von 20 Wochen wurden für jeweils drei Wochen mit dem Versuchsfutter gefüttert. Dazu wurden in acht Versuchsdurchgängen je sechs Hennen/Gruppe gehalten. Neben den Leistungsdaten (Futteraufnahme, Legeleistung, Futteraufwand) wurde die scheinbare ileale Verdaulichkeit von Rohprotein, Aminosäuren, Rohfett und Stärke sowie der pH-Wert der Digesta in verschiedenen Abschnitten des Magen-Darm-Traktes ermittelt. Während der ersten beiden Versuchswoche war die Futteraufnahme der Hühner bei Gabe des mehlförmigen Futters höher verglichen mit den Hühnern, die expandiertes Futter erhielten (p = 0,003; p = 0,023). Die scheinbare ileale Verdaulichkeit der Stärke war bei den Hühnern, die mehlförmiges Futter erhielten, gegenüber Expandat erhöht (p < 0,001) und korrelierte positiv mit der Partikelgröße des Futters (p-linear = 0,001; pquadratisch = 0,006; r = 0,363). Die scheinbare ileale Verdaulichkeit von Rohfett korrelierte hingegen negativ mit der Partikelgröße (p-linear = 0,003; p-quadrat = 0,225; r = -0,311). Auch der pH- Wert des Ileuminhaltes (p-linear = 0,044; p-quadrat = 0,146; r = 0,212) und der Exkremente (p-linear = 0,010; p-quadratisch = 0,016; p = 0,267) korrelierte positiv mit der Partikelgröße. Als Schlussfolgerung ergibt sich aus den durchgeführten Studien, dass hinsichtlich der in der Literatur beschriebenen positiven Wirkungen organischer Säuren als Futterzusatzstoffe hinsichtlich der physiologischen Mechanismen weiterer Untersuchungsbedarf besteht, da sich unter den vorliegenden experimentellen Bedingungen kein Effekt auf die Stärkeverdaulichkeit und die intestinale Nährstofftransportfunktion abzeichnete. Es konnte bestätigt werden, dass eine gröbere Futterstruktur unabhängig von der Zerkleinerungsmethode günstige Effekte auf die scheinbare Stärkeverdaulichkeit bei Legehennen hatte. Insofern sollten innovative energiesparende Mahlverfahren weiter entwickelt werden, die gleichzeitig eine gröbere Partikelstruktur ermöglichen. Die ernährungsphysiologischen Konsequenzen sollten bei technologischen Weiterentwicklungen überprüft werden

Detection of Ascaridia galli in free-range laying hens

Reliable methods for detection of A. galli infection using excreta egg count (EEC) and ELISA assays to determine A. galli specific IgY levels in serum and yolk samples were compared from hens infected naturally and artificially. Artificially infected hens were used to generate samples for analysis of preferred detection methods and to generate contaminated ranges for use in the naturally acquired infection study in which Lohmann Brown hens (n = 200) at 16 weeks of age were randomly assigned to four treatments with five replicate pens. Hens of negative control (NC) ranged on a decontaminated area, hens of low infection, medium infection and positive control (PC) ranged on the areas previously contaminated by hens artificially infected with 250, 1000 and 2500 A. galli eggs/hen, respectively. Additionally, hens of PC were orally infected with 1000 A. galli eggs/hen. Anti A. galli antibody levels in hen serum (SIgY) and yolk (YIgY) were measured before range access, and 2, 7 and 12 weeks after access to the contaminated ranges. In a natural infection study, eggs were detected in the excreta of all hens 4 weeks after range access, with the exception of NC in which no eggs were detected. EEC increased to reach maximum value (2204 ± 307 eggs/g) after 11 weeks of range access and then declined at 12 weeks (905 ± 307eggs/g) (