Joy A. Mench

Hen welfare in different housing systems

Egg production systems have become subject to heightened levels of scrutiny. Multiple factors such as disease, skeletal and foot health, pest and parasite load, behavior, stress, affective states, nutrition, and genetics influence the level of welfare hens experience. Although the need to evaluate the influence of these factors on welfare is recognized, research is still in the early stages. We compared conventional cages, furnished cages, noncage systems, and outdoor systems. Specific attributes of each system are shown to affect welfare, and systems that have similar attributes are affected similarly. For instance, environments in which hens are exposed to litter and soil, such as noncage and outdoor systems, provide a greater opportunity for disease and parasites. The more complex the environment, the more difficult it is to clean, and the larger the group size, the more easily disease and parasites are able to spread. Environments such as conventional cages, which limit movement, can lead to osteoporosis, but environments that have increased complexity, such as noncage systems, expose hens to an increased incidence of bone fractures. More space allows for hens to perform a greater repertoire of behaviors, although some deleterious behaviors such as cannibalism and piling, which results in smothering, can occur in large groups. Less is understood about the stress that each system imposes on the hen, but it appears that each system has its unique challenges. Selective breeding for desired traits such as improved bone strength and decreased feather pecking and cannibalism may help to improve welfare. It appears that no single housing system is ideal from a hen welfare perspective. Although environmental complexity increases behavioral opportunities, it also introduces difficulties in terms of disease and pest control. In addition, environmental complexity can create opportunities for the hens to express behaviors that may be detrimental to their welfare. As a result, any attempt to evaluate the sustainability of a switch to an alternative housing system requires careful consideration of the merits and shortcomings of each housing system.

Animal neuropsychology: Validation of the Intra-Dimensional Extra-Dimensional set shifting task for mice

Research in animal neuropsychology is providing an exciting new generation of behavioral tests for mice that promise to overcome many of the limitations of current high-throughput testing, and provide direct animal homologues of clinically important measures in human research. Set shifting tasks are some of the best understood and widely used human neuropsychological tasks, with clinical relevance to traumatic brain injury, schizophrenia, autism, obsessive compulsive disorder, trichotillomania, and many other disorders. Here we report the first successful modification of a human set shifting neuropsychological task, the Intra-Dimensional Extra-Dimensional (IDED) task, for use with mice. We presented mice with a series of compound discrimination and reversal tasks where one stimulus dimension consistently cued reward. Task performance improved with a new set of compound stimuli, as did reversal performance--indicating the formation of a cognitive-attentional set. We then overtrained a subset of the mice, and presented control and overtrained mice with a new compound discrimination where a novel stimulus dimension cued reward. As is the case in human control subjects, control mice persisted in responding to the now-incorrect stimulus dimension, performing poorly on this extra-dimensional shift compared with the previous intra-dimensional shift, thereby validating the task as a measure of set shifting. Furthermore, overtrained mice were impaired on this extra-dimensional shift compared with controls, further validating the task. The advantages and disadvantages of the IDED task compared to high-throughput approaches are discussed.

Reliability and validity of a modified gait scoring system and its use in assessing tibial dyschondroplasia in broilers

1. The gait scoring system for broilers developed by Kestin et al . ( Veterinary Record , 131: 190-194, 1992) has been widely used to evaluate leg problems. The many factors and measures associated with this scale have empirically established its external (biological) validity. However, published test-retest (within-observer) reliabilities are poor, and inter-observer reliabilities are unknown. We evaluated several modifications to this scale aimed at improving its objectivity and reliability. 2. Eighteen naïve observers scored a standardised video of birds exhibiting varying degrees of lameness, either using Kestin et al .s system, or our modified system. 3. Test-retest reliability (0.906) for Kestin et al .s system was higher than previously reported. Interrater reliability was also good (0.892). The modified system offered significantly better test-retest (0.948) and inter-rater reliabilities (0.943), without incurring costs in terms of time taken or difficulty of use. The systems were consistent, assigning individual birds the same score on average. 4. It is concluded that the modified system offers the advantages of reduced error within and between studies. 5. In a second experiment, we used our modified scoring system to examine the relationship between tibial dyschondroplasia (TD) and gait score in 267 selected broilers. 6. Neither the presence nor severity of TD affected gait score, suggesting that, at least in this strain of broilers, other leg problems like slipped tendons or torsional deformities had more influence on gait impairment than did TD.

Foraging opportunity and increased physical complexity both prevent and reduce psychogenic feather picking by young Amazon parrots

Abstract Although many authors have suggested that the quality of the cage environment contributes to the development and performance of psychogenic feather picking by parrots, there is little scientific evidence for this relationship. In chickens, there is an established relationship between absence of foraging opportunity and the performance of a similar behavior, feather pecking. Thus, we assessed whether providing environmental enrichments designed to facilitate foraging behaviors would prevent or reduce the development of feather picking behavior by parrots, as evidenced by superior feather condition. Two groups of eight parrots were parent-reared to weaning and then housed singly in either enriched or unenriched cages for 48 weeks. In the enriched condition, a unique combination of one foraging and one physical enrichment was presented to each parrot weekly. In both groups, feather condition was quantified using a 10-point scale. The provision of enrichments led to an improvement in feather condition over 48 weeks in the enriched group, while feather scores in the control group decreased significantly (repeated measures GLM: F 1,46 =5.59; P =0.022) during this same period, indicating that feather picking behavior had developed in this group. In the second part of this study, the control group was transferred to the enriched treatment for a period of 16 weeks. During this period re-feathering occurred and feather scores improved significantly, indicating that feather picking behavior had decreased (repeated measures GLM: F 1,53 =35.57, P

The effect of light intensity on the behavior, eye and leg health, and immune function of broiler chickens

Broilers are typically raised commercially in dim lighting. It has been suggested that providing brighter light intensity could improve health and provide opportunities for more normal behavioral rhythms. We examined the effects of 3 photophase light intensities (5, 50, and 200 lx) on activity patterns, immune function, and eye and leg condition of broilers (n = 753; 6 replicate pens/treatment). Broilers were reared with one of these intensities from 1 to 6 wk of age; photoperiod consisted of 16L:8D with 1 lx intensity during the scotophase. Broilers reared with 5 lx were less active (P = 0.023) during the day than 50 or 200 lx and showed less (P < 0.0001) change in activity between day and night than 50 or 200 lx. There was no difference between treatments for final BW (2.30 +/- 0.02 kg) or for most immune parameters (IgG primary and secondary responses to keyhole limpet hemocyanin, B and T lymphocyte proliferation, plasma lysozyme, haptoglobin, NO, whole blood killing of Escherichia coli and Staphylococcus aureus), but there was a trend (P = 0.072) for a greater IgM response in 50 lx (6.21 titer) than 5 lx (5.78 titer), with 200 lx (5.92 titer) intermediate. There was no effect of light intensity on back-to-front (1.13 +/- 0.01 cm) or side-to-side (1.48 +/- 0.01 cm) diameter of the eyes or on corneal radii (0.82 +/- 0.01 cm), but 5 lx (2.33 +/- 0.07 g) had heavier eyes (P = 0.002) than 50 lx (2.09 +/- 0.04 g) or 200 lx (2.11 +/- 0.04 g). There were no differences in gait score, although 200 lx broilers had more hock and footpad bruising (P = 0.038) but fewer erosions (P = 0.006) than 5 or 50 lx. Increased daylight intensity had little effect on broiler health but resulted in more pronounced behavioral rhythms.

Performance, Livability, and Carcass Yield of Slow- and Fast-Growing Chicken Genotypes Fed Low-Nutrient or Standard Diets and Raised Indoors or with Outdoor Access

Two experiments were conducted to assess the effect of genotype, production system, and nutrition on performance and livability of meat chickens for niche markets. Slow-growing (SG) and fast-growing genotypes (FG) were raised for 91 and 63 d, respectively, in experiment 1 (females) or 84 and 56 d, respectively, in experiment 2 (males). In each trial, SG were placed before FG to achieve a similar BW at processing. In experiment 1, each genotype was assigned to 8 pens of 20 birds each, with 4 pens within each genotype raised indoors in a conventional research facility or in a small facility with outdoor access. All birds were fed a low-nutrient diet. In experiment 2, genotype assignment to pens was as in experiment 1; however, 4 pens within each genotype were fed a low-nutrient diet or a conventional diet, and birds were raised indoors. Birds were gait-scored and commercially processed; legs were examined for tibial dyschon-droplasia lesions and scanned for bone mineral density. In experiment 1, FG gained more weight than SG (P < 0.05) even though they were placed later. Outdoor access increased feed intake, and feed efficiency was poorer (P< 0.05). Fast-growing genotypes had higher breast meat yield, whereas SG had higher wing and leg yields (P < 0.05). In experiment 2, the low-nutrient diet reduced (P< 0.05) gain of the SG; FG increased feed intake of the low-nutrient diet such that their gain was unaffected (P> 0.05). For FG, the low-nutrient diet resulted in a poorer (P < 0.05) feed efficiency. Although weight gain of the FG was maintained on the low-nutrient diet, breast yield was reduced (P < 0.05). Genotype affected bone health in both experiments, with SG having better gait scores and less tibial dyschondroplasia (P < 0.05). Outdoor access and the low-nutrient diet also resulted in better gait score (P < 0.05). These data indicate differences among genotypes and provide information about the efficiency and potential for alternative poultry systems.

Is fearfulness a trait that can be measured with behavioural tests? A validation of four fear tests for Japanese quail

If fearfulness is stable, consistent and trait-like, then valid measures of fearfulness should be stable, consistent and independent of influences unrelated to fear. We assessed the validity of six fear measures using Japanese quail, Coturnix coturnix japonica, a common species in fear research. Measures were made during emergence, novel object, novel food and predator surprise tests. These were considered to have internal validity if they were stable over 18 days, when we controlled for nonexperimental variables including season of testing and cage location. We determined convergent and discriminant validity by factor analysis of fear measures plus measures of sociality, activity level and repetitive behaviour. Fear measures with good convergent validity showed agreement in their factor loadings. Those with good discriminant validity loaded on to different factors from nonfear measures. Most of the fear measures examined were moderately stable over time, but only half had good discriminant validity. Convergence was good among measures from the same test but poor across tests. Measures from each fear test loaded separately. Overall, flight distance and freezing duration in the predator surprise test and amount eaten in the novel food test showed the best internal, convergent and discriminant validity. When we considered only these three measures, convergence remained higher among measures from the same test than from different tests. Fearfulness thus appeared somewhat unstable over time and inconsistent across situations, which, if true across species, greatly limits the utility of fear tests.

Environmental enrichment affects the fear and exploratory responses to novelty of young Amazon parrots

The development of techniques to reduce fear responses of captive animals is important because fear is generally considered an undesirable emotional state that is related to increased risk of injury and decreased biological functioning. We tested the effects of environmental enrichments designed to increase the physical complexity of the cage and to provide opportunities for foraging behaviors on responses to novelty of young Orange-winged Amazon parrots (Amazona amazonica). Parrots (n ¼ 16) were housed in either barren or enriched conditions for 1 year and responses to novel objects and human handlers were tested periodically. Parrots in the enriched condition had significantly shorter latencies to approach novel objects placed in their home cages than parrots from the control group (repeated measures GLM: F1;13 ¼ 8:00; P ¼ 0:014). In addition, parrots from the enriched condition had shorter bouts of interaction (F1;14 ¼ 27:93; P < 0:0005) and spent significantly less time interacting with novel objects overall (F1;14 ¼ 27:93; P < 0:0005). Taken together, these results suggest that enrichment reduced both the fear response to novel objects and the motivation to explore and interact with those objects. When tested with a familiar handler, the control parrots had significantly higher response scores (i.e. they were less aggressive and more interactive) than the parrots from the enriched group (t-test; P < 0:005). This suggests that parrots housed in barren conditions may be more motivated to interact with familiar humans as a source of environmental stimulation. All parrots showed higher response scores to familiar than unfamiliar handlers, but in the control group there was a significant drop in score from the familiar to the unfamiliar handler (t-test; P < 0:0005) while in the enriched group the scores with familiar and unfamiliar handlers were similar. Thus, environmental enrichment reduced fear responses to both novel objects and unfamiliar human handlers. Factor analysis revealed that the responses to the novel object and novel human tests were independent, which implies that they did not measure the same underlying factor. Similarly, the

Isosexual pair housing improves the welfare of young Amazon parrots

It has been suggested that isolation from conspecifics may contribute to the development of abnormal behaviors that are common in captive parrots, including stereotypy, feather plucking, excessive fearfulness and aggression (e.g. [Proceedings of the European Symposium on Bird Diseases, Beerse, Belgium (1987), p. 98; Kleintierpraxis 38 (1993) 511]). Thus, we assessed the influence of isosexual pair housing on the development of these behaviors, as well as the incidence of illness and injury, in young Orange-winged Amazon parrots (Amazona amazonica). Parrots (n=21) were parent raised to 6 months of age and then housed either singly or in isosexual pairs. All cages included inanimate enrichments that were changed regularly, and all parrots were handled regularly. Behavioral activity was recorded 0,3,6,9 and 12 months after the parrots were housed in the experimental cages, and responses (e.g. willingness to approach, tolerance to touch, flight distance) to familiar and strange human handlers and to novel objects introduced into the home cage were recorded periodically. Paired parrots used their enrichments more (GLM: F1,10=13.74; P=0.004), and spent less time screaming (F1,10=4.90; P=0.051), less time preening (F1,10=5.12; P=0.047), and less time inactive (F1,10=9.24; P<0.012) than singly housed parrots. Time spent climbing, walking and flying decreased in both groups during the study, but the decrease was greater in the singly housed parrots (F1,54=4.50; P=0.038). None of the paired parrots developed stereotypy by month 12, while 57% of the singly housed parrots did. Responses to familiar handlers did not differ, but paired parrots responded increasingly significantly less fearfully and aggressively to unfamiliar handlers during the study than did singly housed parrots (F1,54=6.37; P=0.015). Latency to approach novel objects was significantly reduced in the paired group when the two birds were tested together (F2,15=7.69; P=0.005). No parrots in the single group sustained injuries while 21% of the parrots in the paired condition experienced injuries, although none of these could be directly linked to intra-pair aggression. Rates of illness did not differ between the two groups. Isosexual pair housing resulted in a more active and diverse behavioral repertoire, eliminated the development of stereotypy and reduced fear responses to novel objects without imparting significant risk of illness and injury or jeopardizing the ability of parrots to relate positively with humans. Thus, it appears that pair housing can significantly improve environmental quality and positively affect the welfare of captive parrots.

Effect of Tryptophan Treatment on Self-Biting and Central Nervous System Serotonin Metabolism in Rhesus Monkeys (Macaca mulatta)

Two studies were conducted to examine the effects of oral L-tryptophan (TRP) supplementation as a treatment for self-injurious behavior (SIB) and to investigate behavior and central serotonin turnover of male rhesus monkeys. In Study One, TRP was administered to seven individually housed rhesus monkeys with a recent history of spontaneous SIB. While the monkeys were on TRP treatment (100 mg/kg twice a day), cisternal cerebrospinal fluid (CSF) concentrations of 5-hydroxyindoleacetic acid increased markedly (p=.0013) above baseline (baseline mean=207.6 pmol/ml ± 39; TRP mean=320.3 pmol/ml ± 83.4), and the duration of self-biting behavior decreased below baseline (p=.03). In Study Two, 14 individually housed rhesus monkeys without a history of SIB were placed on three different doses of TRP in random order (50, 100, and 200 mg/kg twice a day). TRP had no effect on any behavioral or biochemical variables in the normal monkeys. Conclusions: Supplemental tryptophan in well-tolerated doses reduced self-biting and increases serotonin turnover rate in male monkeys with a recent history of SIB. The same doses of TRP do not affect behavior or serotonin metabolism in male monkeys without a history of SIB.