Well-being Of Hens Research Articles

Animal Welfare and Human Ethics: A Personality Study

We elicit concern for animal welfare in an incentivized, direct and real setup that allows us to separate genuine interest in animal welfare from confounding factors like advertisement, replacement arguments or image concerns. Subjects choose between intensive farming and organic living conditions for a laying hen. Opting for better living conditions is costly, but guarantees better food, daylight, and more space to the hen. Hence subjects have to trade off a selfish benefit (money) against the welfare of a hen. Our data shed light on a long-standing philosophical debate about the relationship between animal welfare and human ethics. We confirm that subjects with higher interests in the hen's well-being exhibit higher moral standards towards humans. Supporters of intensive farming are significantly less prosocial and open-minded, and more Machiavellian than others.

Comportamento de poedeiras criadas a diferentes densidades e tamanhos de grupo em ambiente enriquecido

O objetivo deste trabalho foi determinar diferenças comportamentais entre poedeiras criadas sob diferentes densidades e tamanhos de grupo, em condições de ambiente enriquecido. Foram utilizadas poedeiras Isa Brown com idade entre 30 e 32 semanas alojadas em galpões de escala reduzida e distorcida. As aves foram criadas durante 28 dias, em baias com cama de maravalha, poleiro e ninho. Foram avaliados dois tamanhos de grupos (6 e 12 aves) e duas densidades de criação (774 e 1.440 cm² por ave), em arranjo fatorial com três repetições. Em amostras de vídeo de 15 min, foram registrados as frequências e os tempos de expressão dos comportamentos: arrumar penas, banho de areia, bater asas, beber água, bicar, coçar a cabeça, ciscar, comer, empoleirar, esticar perna, perseguir, sentar e visitar o ninho. Foram observados efeitos significativos dos tratamentos e da interação entre eles. O grupo de seis aves manifestou aumento da frequência de comportamentos que indicam maior frustração das aves, independentemente da densidade. O tamanho de grupo é o fator mais importante para o bem-estar das aves.

Genetic variations alter production and behavioral responses following heat stress in 2 strains of laying hens

Genetic differences alter the type and degree of hens’ responses and their ability to adapt to a stressor. This study examined the effects of genotypic variations on the productivity and behavior of laying hens following heat stress (HS). Two strains of White Leghorn hens were used: DXL (Dekalb XL), a commercial strain individually selected for egg production and KGB (kind, gentle bird), a strain selected for high group productivity and survivability. Ninety hens (48 DXL and 42 KGB) at 28 wk of age were randomly assigned to either a hot (H: mean = 32.6°C) or control (C: mean = 24.3°C) treatment and housed in pairs by strain for 9 d. Egg production and quality, behavior, body and organ weights, and circulating hormone concentrations were measured. Heat-stressed hens had lower egg production [adjusted (adj) P < 0.001] than their respective controls. Among H-DXL hens, egg weight tended to be reduced at d 1 and was reduced at d 9 (adj P = 0.007), but was reduced only at d 9 among H-KGB hens (adj P = 0.007). Eggshell thickness was also reduced among H hens at d 9 (adj P = 0.007), especially among H-KGB hens (adj P = 0.01). Plasma triiodothyronine concentration was reduced among H-hens (adj P = 0.01), especially among H-DXL hens (adj P = 0.01). Neither temperature nor strain affected the plasma thyroxine and plasma and yolk corticosterone concentrations. Heat-stressed hens spent less time walking (adj P = 0.001) and more time drinking (adj P = 0.007) and resting (adj P = 0.001) than C-hens. The results indicate that although HS reduced production and caused behavioral changes among hens from both strains, the responses differed by genotype. The data provide evidence that genetic selection is a useful strategy for reducing HS response in laying hens. The results provide insights for conducting future studies to develop heat-resistant strains to improve hen well-being, especially under the current commercial conditions.

Intensive versus extensive management systems in commercial egg production.

Abstract Despite the degree of environmental protection and economic feasibility offered by traditional poultry production systems, the practice of housing laying hens in cages has been widely criticized worldwide because of the public perception that caged housing systems provide poor welfare for laying hens. As a result of increasing public interest in laying hen welfare, alternative management systems such as free-range environments have been resurrected and new legislation such as the California Proposition Two is expediting a shift back towards extensive practices. The transition from intensive back to extensive practices coupled with the advent and increasing popularity of novel alternative layer housing management methods in recent years necessitates an examination of the influence of environmental stressors associated with different housing methods on layer egg production, immunological response and reproductive well-being. In this review, the evolution of intensive and extensive management practices is comparatively examined based on how these different management practices impact layer hen well-being and productivity. Different welfare assessment techniques are also examined in an effort to provide insight into the progression of research concerning layer hen welfare in different management systems.

Effects of group size and repeated social disruption on the serotonergic and dopaminergic systems in two genetic lines of White Leghorn laying hens

Farm practices such as increasing group size (GS) and mixing unfamiliar chickens may result in repeated social disruption (RSD) and affect the well-being of hens. To examine whether there are genetic differences in response to social stress, 2 genetic strains of White Leghorn hens were used [i.e., high group production and survivability (HGPS) and DeKalb XL commercial strain (DXL). At 50 wk of age, social stress was created by increasing GS from 4 hens (control) to 8 hens (experimental) per cage and removing hens within the stressed groups to create 4 treatments (control-HGPS, control-DXL, GS/RSD-HGPS, and GS/RSD-DXL). For RSD, 2 hens per cage were moved weekly among the experimental cages within the same treatment. At 58 wk of age, blood sample and brain were collected from 1 hen per cage (n = 10 per treatment). Whole-blood tryptophan and serotonin (5-HT) and plasma norepinephrine (NE), epinephrine (EP), and dopamine (DA) were analyzed by HPLC. The raphe nuclei and the hypothalamus (HYP) were dissected and analyzed by HPLC for the central NE, EP, DA, dihydroxyphenylacetic acid (DOPAC), homovanillic acid, 5-hydroxyindoleacetic acid (5-HIAA), 5-HT, and the ratios of DOPAC:DA and 5-HIAA:5-HT. There were no line differences in the concentrations of peripheral tryptophan, 5-HT, EP, NE, and DA in response to GS-RSD (P > 0.10). However, neuronal transmitters were regulated differently in the different central nuclei between the lines. In the raphe nuclei, control-HGPS tended to have a higher 5-HIAA:5-HT ratio than the control-DXL (P = 0.09). Concentrations of EP were increased in the DXL hens (P < 0.01), whereas the HGPS hens had decreased levels of DOPAC (P < 0.05) and DA turnover (DOPAC:DA, P < 0.01) post GS-RSD. In the HYP, compared with relative controls, there were no significant differences in the concentrations of 5-HT, whereas the levels of 5-HIAA were reduced (P < 0.01) after GS-RSD, suggesting that GS-RSD led to a lower 5-HT turnover in the HYP. The results indicate that selection for docility and productivity alters serotonergic and catecholamine homeostasis in hens in response to social stress, GS-RSD.

Furnished cage system and hen well-being: Comparative effects of furnished cages and battery cages on behavioral exhibitions in White Leghorn chickens

The battery cage system is being banned in the European Union before or by 2012, and the furnished cage system will be the only cage system allowed after 2012. This study was conducted to examine the different effects of caging systems, furnished cages vs. battery cages, on bird behaviors. One hundred ninety-two 1-d-old non-beak-trimmed Hy-Line W-36 White Leghorn chicks were reared using standard management practices in raised wire cages. At 19 wk of age, the birds were randomly assigned into battery cages or furnished cages. The battery cages were commercial wire cages containing 6 birds per cage, providing 645 cm2 of floor space per birds. The furnished cages had wire floors and solid metal walls, with perches, a dustbathing area, scratch pads, and a nestbox area with a concealment curtain. Based on the company recommendations, 10 birds were housed per cage, providing a stocking density of 610 cm2 of floor space per bird. Behavioral observations were conducted using the Noldus Observer software package. The birds were observed at 5-min intervals for the entire light period. The birds housed in battery cages had higher posture and behavioral transitions and increased time spent walking and performing exploratory behavior (P < 0.05, 0.01, respectively), which may indicate they were stressed, resulting in restlessness, whereas the birds housed in furnished cages had higher levels of preening (P < 0.05). Preening has been considered as a comfort behavior in birds. These results may suggest that furnished cages may be a favorable alternative system for housing birds by allowing them to perform certain natural behaviors.

Overview of natural and organic egg production: Looking back to the future

The US egg industry has grown dramatically in the past, with a significant component of that growth focusing on alternative production systems such as cage-free or range egg production. Constituents of this growth involving intensive egg production create uncertainty in relation to the future because of concerns about the impact of the cage environment on laying hen well-being. Both the commercial egg production sector and small producers using heritage strains of chickens, in flocks ranging in size from 100 to 3,000 hens, are responding by producing eggs in both cage-free and range settings. However, one of the current issues is that our knowledge base of how these alternative production methods influence egg performance and quality characteristics is limited to research studies that were conducted in the late 1940s and early 1950s. This information was collected with specific breeds, and not with modern lines of poultry that have been selected for very high rates of egg production. Therefore, an examination of alterative laying hen husbandry practices in the context of the current knowledge base would provide beneficial information to identify how these husbandry and feeding practices translate to modern strains of laying hens under cage-free or range production. Research on range or cage-free production done in controlled settings is limited, and additional studies relevant to egg producers wishing to expand cage-free and range egg production are needed.

Effects of moist litter, perches, and droppings pit on fluctuating asymmetry, tonic immobility duration, and heterophil-to-lymphocyte ratio of laying hens

The purpose of this study was to analyze the effects of moist litter, perches, and droppings pit on the fluctuating asymmetry, the tonic immobility duration, and the heterophil:lymphocyte ratio of laying hens. In experiment 1, hens from 4 Spanish breeds and a White Leghorn population, that had been housed in moist or dry litter pens from 20 wk of age, were used. Treatment effect was significant for the fluctuating asymmetry of toe length (P < 0.05), the fluctuating asymmetry of hens housed in moist litter pens being larger. The duration of tonic immobility was significantly longer (P < 0.01) in hens housed in moist litter pens. Thus, litter moisture is associated with the well-being or fear levels of hens, as indicated by the fluctuating asymmetry and the tonic immobility duration. In experiment 2, hens from the Black Menorca breed, that had been housed in pens with or without perches from 20 wk of age, were used. The fluctuating asymmetry of wattle length and the combined fluctuating asymmetry were significantly greater (P < 0.001) in hens housed in pens without perches. Thus, the presence of perches is associated with the well-being level of birds, as indicated by the fluctuating asymmetry. In experiment 3, hens from 4 Spanish breeds and a White Leghorn population, that had been housed in pens with or without a droppings pit, were used. There was significant difference for the fluctuating asymmetry of leg length (P < 0.001) between hens housed in pens with or without a droppings pit, the fluctuating asymmetry of hens housed in pens without a droppings pit being larger. There were no significant differences for the duration of tonic immobility and the heterophil:lymphocyte ratio between both treatments. Thus, the presence of a droppings pit is associated with the well-being of hens, as indicated by the fluctuating asymmetry, and does not contribute to their fear or stress levels, as indicated by the tonic immobility duration and the heterophil:lymphocyte ratio.

Molting Layers—Alternative Methods and Their Effectiveness

The molting of commercial layers has been under increased scrutiny by animal rights groups, who have said that this practice is highly stressful and one which negatively affects the welfare of the hen due to the initial period of fasting that has been used to stop egg production. In recent years, there has been a recognized need to develop practical alternatives to molting layers other than the use of fasting. Thus, the University of Illinois, University of Nebraska, North Carolina State University, and the University of California have all researched this area. In all of these studies, the methods involved comparing a normal fasting method (i.e., 5 to 13 d), to feeding low-energy and protein diets using ingredients such as wheat middlings, soybean hulls, and corn or diets with graded levels of added salt and without salt (University of Nebraska, University of California). The molt period (28 d) included full-feeding of these diets. In these studies, postmolt production performance for the nonfeed withdrawal techniques was comparable to the fasting method. Several researchers have also evaluated the behavioral repertoire of laying hens, which includes feeding, drinking, comfort, social, reproductive, and anti-predator behaviors. In addition, related behaviors such as aggression, escape-avoidance, and submission have been of particular interest as potential indicators of welfare during molting. In these studies, genetic selection, strain, density, or molt program do not appear to adversely influence the behavioral patterns during the molt. The behavior patterns displayed during a molt program appear consistent with the response to physiological changes that layers experience and do not appear to compromise the welfare status of the hens. Appetitive behaviors were not affected by strain but were affected by production phase and molting. Strain or production phase did not influence the frequency of aggressive and submissive acts. Thus, the use of alternative nonfeed withdrawal molting methods provide comparable laying hen well-being and may enhance the transition from a productive to a resting state.

Effects of Induced Molting on the Well-Being of Egg-Laying Hens

Induced molting in egg-laying hens is an important method for maximizing hen egg production and quality as well as hen health in commercial settings; however, there is growing societal concern over its effects on hen well-being. Using individual hens as their own controls, this research examined the behavior of hens subjected to different treatments of induced molting under premolt, molt, and postmolt conditions. Cage pecking increased in fast-induced subjects and aggression increased in fast-induced and nonfast-induced subjects during the molt. Gakel calling and several aspects of its acoustic structure were much higher during the molt condition in fast-induced subjects only. These data suggest that nonfast-induced molting treatments provide an effective method for inducing molting in hens and improving their well-being by minimizing discomfort due to food deprivation. In addition, these data further support that gakel vocalizations in hens may serve as an effective indicator for assessing well-being in a species otherwise behaviorally stoic in expressing stress or discomfort.

Melengestrol acetate in experimental diets as an effective alternative to induce a decline in egg production and reversible regression of the reproductive tract in laying hens I. Determining an effective concentration of melengestrol acetate

Induced molting increases egg quality and egg production and extends the productive life of hens. Molting is accomplished by feed withdrawal, which has been criticized for not addressing hen well-being, and current alternatives have resulted in poor postmolt performance and inadequate well-being. Molting leads to regression of follicles on the ovary and causes loss of steroidogenic support for the oviduct, leading to cessation of lay. Melengestrol acetate (MGA), an orally active progestin, may decrease support for the ovary, resulting in loss of support for the oviduct, while hens are fed a balanced diet. In this experiment, a dose response study, Hy-Line W-36 hens were fed 0, 0.1, 1, 4, or 8 mg of MGA per hen/d in a balanced diet for 28 d and then returned to a normal diet. Four birds on d 0 and 4 birds per treatment on d 1, 2, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, and 44 were euthanized. The weight of the ovary with follicles, magnum, shell gland, and oviduct were determined. A decrease in egg production was observed in those groups receiving 4 and 8 mg of MGA, until removal of MGA from the diet. After d 28, egg production increased to the production level of hens fed 0, 0.1, or 1 mg of MGA. The weight of the ovary with follicles, oviduct, magnum, and shell gland were unchanged throughout in groups fed 0, 0.1, or 1 mg of MGA. However, groups fed 4 or 8 mg of MGA exhibited a decrease (P < 0.05) in the weight of the ovary with follicles, oviduct, magnum, and shell gland until d 28. Recrudescence of the large yellow follicles as well as rejuvenation of the oviduct and its components, the magnum and shell gland, in the 4 and 8 mg MGA groups occurred by d 44. Melengestrol acetate, fed to hens on a balanced layer diet, caused reversible regression of follicles and, therefore, removal and return of support for the oviduct.

Fearfulness in chickens: Its importance and modification

Although fear is a complex and often controversial concept, most authors have emphasized its motivational, defensive and positive aspects. Indeed, fear is viewed here as an adaptive psychophysiological response to perceived danger. However, exposure to intense, prolonged or inescapable frightening stimulation can have deleterious effects on a hen's wellbeing. For example, fear responses which are inappropriate in an intensive environment may waste energy and injure birds or their cage mates. Increased fearfulness in laying hens has also been associated with increased feather loss and with reduced growth, egg production and eggshell quality. Two of the more influential behavioural modifications accompanying the domestication process have been reductions in the bird's fear of human beings and of sudden changes in its environment. However, the rapid evolution of intensive farming continues to tax adaptability. Thus, while the complete eradication of fearfulness and frightening stimulation is neither attainable nor necessarily desirable, their manipulation, modification and optimalization are considered worthwhile. The domestic fowl's responsiveness to man and to its environment can be modified by pharmacological, genetic, experiential and environmental manipulation and four possible approaches are briefly examined here. They include tranquillization, artificial selection, regular gentle handling or socialization and early environmental enrichment. Selected studies are reviewed and the relative merits and limitations of each approach are discussed. Tranquillization is not recommended, but independent or integrated application of selection, socialization and enrichment programmes may help to modify general fearfulness and deserve further investigation. Some Invest igat ions on Excitabil i ty in Pigs D. BUCHENAUER and M. MAYER Institut fiir Tierzucht und Vererbungsforschung der Tieriirztlichen Hochschule Hannover, Bi~nteweg 17p, D-3000 Hannover I (F.R.G.) ABSTRACT To investigate excitability in pigs, the open field test was used. A total of 1400 piglets were tested, 889 were German Landrace and 511 were a cross-breed between Duroc and German Lan-To investigate excitability in pigs, the open field test was used. A total of 1400 piglets were tested, 889 were German Landrace and 511 were a cross-breed between Duroc and German Lan-

Performance, Behavior, Plasma Corticosterone, and Economic Returns of Laying Hens in Several Management Alternatives

Production, physiological, and behavioral data were collected simultaneously on commercial hens housed for 10 months of lay in housing alternatives of cages, deep litter floor pens, and oustide range pens. Treatments consisted of housing 1, 2, or 3 hens in small cages 3,4, 5, or 6 hens in large cages, floor pens housing 51 hens each at three densities, and range pens with 50 hens at .74 m2 (8 ft2) per hen. Egg production rates were greater for all caged hen treatments than for any floor or range groups. Egg numbers favored 2 hens per cage, but economic benefits favored 5 hens per cage. Viability was highest for 1 hen per cage and range pen groups. Feed efficiency was poorer in floor and range groups; however, body weight was generally greater for caged hens. Plasma corticosterone levels did not differ among any cage or range groups, but floor pen hens had significantly elevated levels. Behavioral data for walking and object pecking showed clear differences between cage and floor management alternatives. Preening, standing, and drinking activities were different between some treatments but not clearly different between management alternatives. Feeding activity did not differ among any groups. Although correlations between stress and well-being have not been well elucidated, the sum of the stressors of cage confinement appeared to be less than those from floor pens. Therefore, it was concluded that the well-being of hens in cages was equal to or better than that for free ranging hens or those in floor pens.

Behaviour and Well-being of Hens (Gallus Domesticus) in Alternative Housing Environments

Widespread concern is evident in some countries, especially those of Western Europe, for the well-being of hens in high-density environments. Evaluation of potentially stressful conditions is diffi...