Comparison of carcass condemnation causes in two broiler hybrids differing in growth rates.

Experimental studies concluded that genetic factors enabling fast growth rate might negatively affect broiler health and welfare. Recently, the proportion of slower-growing broilers has been increasing. However, studies of health in broilers with different growth rates in commercial systems are still scarce. This repeated cross-sectional study aimed to describe causes of carcass condemnations in two broiler hybrids with different growth rates, Ross 308, and Hubbard JA787, and to estimate the effect of hybrid. The study sample consisted of 63,209,415 broilers slaughtered in 4295 batches from 139 farms. All broilers were slaughtered from January 1st, 2015, to June 22nd, 2021, by the same company (Norsk Kylling). All causes of condemnation, except fractures, were more prevalent in Ross 308. The five most common causes (ascites, discolouration, hepatitis, small and skin lesions) were investigated in greater detail, and the effect of hybrid was assessed using mixed effects negative binomial models with the condemnation codes as outcome variables. For the five selected causes, variation in prevalence between slaughter batches was considerable for Ross and minor for Hubbard. The notable differences between hybrids in prevalence and causes of condemnation have important implications for animal health, welfare, economy, and sustainability in broiler production.

Keel bone fractures in broiler breeders: is palpation a reliable diagnostic method?

The aim of this study was to estimate the sensitivity and specificity of palpation relative to necropsy for detection of keel bone fractures (KBF) in broiler breeders. In addition, the study investigated observer reliability of palpation. Four commercial breeder flocks (Ross 308 n = 2, Ranger Gold n = 1, Hubbard JA 757, n = 1) were included in the study. A total of 400 hens and 60 roosters were examined after culling or slaughter, at end of lay (63 weeks). Keel bones were first palpated independently by two raters with a varying degree of experience in palpation of keel bones in laying hens. After palpation, a necropsy with investigation of the keel bone was conducted. The prevalence of KBF at end of lay for hens, as diagnosed by necropsy, varied from 14-58%, while only one in 60 assessed roosters had KBF. Palpation had poor sensitivity, with differences between raters ranging from 56% to 36% when hybrid is not considered. The specificity of palpation for all hybrids together was 85% and 88%, for the two raters, respectively. The two raters had moderate agreement, Gwet's agreement coefficient (95% confidence interval): 0.60 (0.52-0.69). In conclusion, palpation has poor diagnostic accuracy for detection of KBF in broiler breeders, and other methods, like necropsy, must be applied for reliable assessments. KBF appears to be a prevalent condition in different hybrids of broiler breeder hens, but not in roosters.RESEARCH HIGHLIGHTS This is the first study to investigate palpation as a diagnostic method for detection of KBF in broiler breeders.Palpation has poor diagnostic accuracy for detection of KBF in broiler breeder hens with differences between raters.KBF can be a prevalent problem in broiler breeder hens of several hybrids, but not in roosters.

Can shelter dog observers score behavioural expressions consistently over time?

A substantial number of dogs live in animal shelters worldwide. Stressors within the shelter environment can compromise their welfare, and scientific evaluations of feasible welfare assessment methods are therefore needed. Qualitative Behaviour Assessment (QBA) is a "whole-animal" approach used to assess welfare by observing animals' expressive behaviour. To investigate whether observers can score dogs' behavioural expressions consistently over time, this study replicated and extended previous research, by evaluating intra- and inter-observer reliability of QBA based on video recordings of shelter dogs. In Part I, nine veterinary nurse students received theoretical and practical training, and then scored 12 2 min video recordings of shelter dogs using a fixed list of behavioural descriptors. Three of the students undertook further practice and calibration using direct observations of dog behaviour in a local shelter. In Part II, the videos from Part I were scored by these three observers a second time, 15 months later. QBA data were analysed using principal component analysis (PCA), and reliability was assessed using Kendall's coefficient of concordance (W). In Part I, the inter-observer reliability was high for both components (0.78 for PC1 and 0.85 for PC2). In Part II, the inter-observer reliability was very high and moderate for PC1 and PC2, respectively (0.90 for PC1 and 0.65 for PC2). The intra-observer reliability was high for both components (W ≥ 0.86). Our results indicate that the fixed list of behavioural descriptors for shelter dogs can be used reliably when assessing videos, and that observers can score dogs' behavioural expressions consistently after a break of 15 months following the initial assessment. Nevertheless, the reduction in inter-observer-reliability of PC2 in Part II can indicate that some retraining and calibration may be required to avoid observer drift.

Flock Factors Correlated with Elevated Mortality in Non-Beak Trimmed Aviary-Housed Layers.

The use of non-cage housing systems for layers is increasing in Europe and elsewhere. Knowledge of factors that may affect mortality in these systems is important to be able to improve animal welfare, reduce mortality and enhance sustainability. The aim of this study was to investigate factors that may contribute to increased mortality in non-beak trimmed aviary-housed laying hens in Norway. A total of 39 non-beak trimmed commercial flocks (Lohmann LSL (n = 25) and Dekalb White (n = 14)) were visited between week 70 to 76 of life, and factors related to health, behaviour and management were recorded. Mean mortality in the flocks was 3% (range: 0.5−9%) and increased flock mortality was correlated with total feather loss (p < 0.05); feather loss on the breast (p < 0.02) and feather loss on the head (p < 0.003). There was an association between layer hybrid line and mortality (p = 0.055). Furthermore, a low positive correlation between mortality and dust level inside the barn was found (p < 0.04), showing that mortality was higher when dust level was also high. No correlation between mortality and the provision of environmental enrichment was found. In conclusion, this study found an association between flocks with elevated mortality (>3.0%) and increased feather loss which may indicate feather pecking. The results underline the importance of regularly assessment of plumage condition in commercial layer farms, as a tool to detect early signs of feather pecking in commercial aviary-housed layer flocks. This may help to target feather pecking before cannibalism breaks out.

Keel bone fractures are more prevalent in White Leghorn hens than in Red Jungle fowl hens-A pilot study.

Fractures and deviations to the keel bone are common in commercial laying hens, with reported variations in occurrence across strains and breeds. The aetiology is not fully understood, however, modern genetics and selection for efficient egg production has been claimed to be important factors for the keel bone fractures. To explore this further, we investigated keel bones from two different breeds, representing different degrees of selection for egg production: Red jungle fowl (n = 82), and White Leghorn (n = 32), where the latter is a selected laying breed which is the origin for many modern laying hen hybrids. Keel bones from a total of 116 birds, 53 hens and 63 roosters, were examined by necropsy at 80 weeks of age. All birds were raised in modified aviaries in the same holding facility. Overall, 24.5% of the hens had one or more fractures to the keel, with a difference in the prevalence between hens from the two breeds (p<0.01): 10% (95% CI: 3.7-24%) in the Red Jungle fowl hens and 69% (95% CI: 37-90%) in the White Leghorn hens. No roosters, regardless of breed, had keel bone fractures. Mild to moderate keel bone deviations were present in 54% (95% CI: 25-80%) of the hens and 4.7% (95% CI: 0.5-30%) of the roosters, all White Leghorns.

Reliability of observer ratings: Qualitative behaviour assessments of shelter dogs using a fixed list of descriptors.

Qualitative Behaviour Assessment (QBA) is a whole-animal approach used to quantify the expressive style of animals' behaviour. The aim of this study was to evaluate the inter-observer reliability of QBA of shelter dogs using a fixed list of descriptors. The fixed list of 20 terms was generated using a group of experts and literature reviews. In the pilot study, seven veterinary students scored 12 two-minute video clips, and in the main study, 22 final year veterinary nurse students and third-year veterinary students scored the same videos. The two datasets were analysed using Principal Component Analysis (PCA), and the level of agreement for the main components and individual terms was assessed using Kendall's coefficient of concordance (W). In the pilot study, the observer agreement was 0.89 for PC1 and 0.78 for PC2, indicating high inter-observer agreement. The reliability was similarly high for both components in the main study (0.88 and 0.79, respectively). Results also demonstrated high or moderate agreement for most of the terms included in the fixed list. We propose that this approach can be a useful learning tool for students. Our results support further exploration of this method for the assessment of shelter dog welfare by direct observation.

A Descriptive Study of Keel Bone Fractures in Hens and Roosters from Four Non-Commercial Laying Breeds Housed in Furnished Cages.

The presence of keel bone fractures (KBF) in laying hens has been documented and discussed by several authors, nevertheless the causative factors behind KBF remain uncertain. High prevalence of KBF have been reported in all commercial egg production systems, in different genetic lines and at different ages. Several of the proposed causal mechanisms behind KBF are linked to selection for efficient production. It is, therefore, of interest to explore whether less selected breeds have a lower occurrence of keel bone fractures compared to reports from highly selected, modern laying hen breeds. Thus, the aim of the current study was to investigate keel bones of hens from four non-commercial layer breeds. Birds were housed in furnished cages and keel bones examined at 30 and 63 weeks of age, using a portable X-ray equipment. The results from this descriptive study indicate a low prevalence of KBF at both ages in all four breeds, with only five KBF detected in 213 X-ray pictures taken from 126 birds. Of these, four of the KBF were observed in the most genetically selected breed, with an early onset of lay. None of the roosters examined exhibited KBF. The overall low numbers of KBF found indicate that genetic factors may be involved in KBF and, thus that selective breeding may help to reduce the susceptibility to KBF. Finally, this study highlights the importance of poultry conservation to secure genetic diversity, which may be an important resource in future selection schemes.

Prevalence of Keel Bone Damage in Red Jungle Fowls (Gallus gallus)-A Pilot Study.

Keel bone damage (KBD) is a highly prevalent problem in commercial egg production. KBD consists of two different conditions affecting the keel: Keel bone deviation and keel bone fractures (KBF). Deviations are linked to pressure on the keel, e.g., from perching. The causative factors for KBF are not clear; however, selection for efficient egg production has been suggested as a major contributing factor. An important step to shed light on the role of selective breeding as an underlying cause of KBF in modern laying hens is to evaluate the keel bones of the ancestor, the red jungle fowl. To the authors' knowledge, this has never previously been published. The aim of this study was therefore to describe the prevalence of KBD in a study group of red jungle hens and roosters housed in an aviary system. The present study examined 29 red jungle fowls 112 weeks of age post-mortem; 12 hens and 17 roosters. Keel bones were evaluated by external palpation for deviations and fractures. Palpation was followed by autopsy. No fractures were detected in the 17 roosters; one had a very slight deviation. Of the 12 red jungle hens in this pilot study, one had a single fracture and 10 hens had a very slight deviation.

Associations between carcass weight uniformity and production measures on farm and at slaughter in commercial broiler flocks.

In poultry flocks, flock weight uniformity is often defined as the percent individuals within 10% of the mean body weight (BW) and the variability of this uniformity can be expressed as the CV of BW. Flock weight uniformity is a standardized and objective measured, and could potentially be used as a welfare indicator; however, little is known about the relationship between flock uniformity and other production measures on-farm or at slaughter. The aim of this study was to investigate the associations between carcass weight uniformity (CV of BW) and production measures on-farm and at slaughter in Norwegian commercial broiler flocks. A total of 45 randomly selected mixed-sex Ross 308 broiler flocks were visited prior to slaughter at 28 to 30 D of age (average slaughter age 30.6 D). All flocks were raised under similar farm management systems. The Welfare Quality protocol for broilers was used to assess different animal welfare indicators in each flock. All production data from the slaughterhouse were collected for each flock, including carcass weight uniformity (%), mortality (%), growth rate (g), feed conversion ratio (FCR), and rejected birds (%) in different rejection categories. Univariable and multivariable linear regression models were used to investigate the associations between flock weight uniformity and production and welfare measures. The results showed that flock uniformity varied from 11% to 18% between flocks within the same hybrid, similar management standards, and similar slaughter age (day 29 to 32). Poorer uniformity (i.e., high CV) was associated with increased first week mortality (P < 0.004, r = 1.48, increased total mortality (P < 0.013, r = 0.01), increased FCR (i.e., less efficient growth) (P < 0.024, r = 0.06), reduced growth rate (P < 0.0012, r = -0.01), and a reduced rejection rate at slaughter (P < 0.006, r = -0.01). The results show that flock uniformity varies across broiler flocks, and is associated with several production measures.

Effects of environmental enrichment on activity and lameness in commercial broiler production.

The aim of this pilot study was to investigate the effects of commercially applied environmental enrichments on behavior and lameness in broilers. Two consecutive flocks of broilers were observed at 16 days and 30 days of age to investigate differences between enriched (peat, bales of lucerne hay, and elevated platforms) and control birds with regards to behavioral activities and lameness. More running (p < .001), worm running (p = .006), play fighting (p = .015), dust bathing (p = .009), and ground pecking while standing (p < .001) were observed at 16 days than at 30 days. Across both ages, enriched birds showed more wing flapping (p = .016), wing stretching (p = .002), body shaking (p = .002), ground scratching (p < .001), and ground pecking while standing (p < .001) and lying (p = .003) compared with control birds. Even when no enrichments were close, enriched birds showed more body shaking (p = .008) and ground pecking while standing (p < 0.001) and lying (p = .010) than birds in comparable locations in control pens. There was a tendency for a lower gait score (i.e., reduced lameness) with the enriched treatment (p = .077). In conclusion, enriched birds showed higher levels of several activities compared with control birds, and demonstrated higher levels in areas where no enrichments were present.

Tail Tip Lesions in Mink (Neovison vison): Effects of an Additional Hammock in Multilevel Cages.

The occurrence of wounds in different anatomical regions, such as tail tip lesions, is an important welfare concern in farmed mink. This study investigated whether mechanical factors attributed to cage design in multilevel cages may be involved in the etiology of tail tip lesions. Specifically, effects of an additional hammock intended to reduce speed during transitions between cage levels and thereby assumed to lower the incidence and severity of tails hitting the wire mesh were investigated. Three mink farms and a total of 600 mink participated in the study. On each farm, brown female mink (n = 100) were either housed in multilevel cages equipped with plastic hammocks (placed either perpendicular or parallel to the sidewalls) or in standard multilevel cages without hammocks (n = 100). The study was conducted from December to March using singly housed females. Significant differences in the number of tail tip wounds were found between groups with a hammock installed in the cage vs. control groups in two of the farms (p = 0.029 and p = 0.031), with more wounds developing in cages without a hammock. Furthermore, there was a trend towards difference in the number of tail tip wounds in groups with hammocks installed perpendicular vs. groups with hammocks installed parallel to the cage sidewalls, but a potential farm effect cannot be ruled out. This study is the first to suggest that mechanical factors associated with cage design may play a role in the etiology of tail tip lesions in farmed mink. Further studies are needed to understand the causal relationship between cage design and tail tip lesions in mink.

An Evaluation of Two Different Broiler Catching Methods.

Catching is the first step in the pre-slaughter chain for broiler chickens. The process may be detrimental for animal welfare due to the associated handling. The aim of this pilot study was to compare two different methods to manually catch broilers: Catching the broilers by two legs and carrying them inverted (LEGS) or catching the broilers under the abdomen and carrying them in an upright position (UPRIGHT). Wing and leg fractures upon arrival at the abattoir, animal density in the drawers, birds on their back, broilers dead-on-arrival and time to fill the transport modules were investigated. The results showed that mean crating time was shorter in the UPRIGHT method (p = 0.007). There was a tendency for more wing fractures in broilers caught by the LEGS (p = 0.06). The animal density in the drawers was lower and with a smaller range in the UPRIGHT method (p = 0.022). The results indicate that catching the broilers under the abdomen in an upright position may improve broiler welfare in terms of fewer wing fractures, more consistent stocking density in drawers and potentially reduced loading time.

Hot chicks, cold feet.

Infrared thermography (IRT) is increasingly applied as a noninvasive technique for measuring surface body temperature alterations related to e.g. stress, emotions and leg pathologies in avian species. As a basis for the validation of IRT as a future tool for veterinary diagnostics such as detection and/or prediction of subclinical footpad pathologies in broiler chickens, this study explored effects of manual restraint at two different ages on footpad temperatures. Head region temperatures were applied as additional measures of emotional arousal and stress. The study demonstrated that footpad temperatures dropped during 10min of restraint (p<0.001, -0.45°C 95% CI (-0.49, -0.41) per min), whilst head region temperatures (e.g. nostril, wattle, eye, and average head temperature) rose (p=0.004, 0.76°C 95% CI (0.39, 1.15) per 10min), which is consistent with body temperature alterations during emotional arousal and stress, termed stress-induces hyperthermia. Temperature differed between 30 and 36 d (p<0.001, 1.71°C 95% CI (1.04, 2.38) per week), but it is impossible to draw conclusions whether this effect was caused by age or by conditioning. Furthermore, sequential sampling order affected temperature (p=0.04, 0.13°C 95% CI (0.01, 0.25)). In conclusion, one needs to take into account the duration of handling and restraint during the assessment of footpad temperatures, as well as the chickens age, previous experience and sequential sampling order, when using IRT technology as a future noninvasive tool to study temperature alterations associated with subclinical footpad pathologies in broiler chickens.

Air Quality in Alternative Housing Systems May Have an Impact on Laying Hen Welfare. Part I-Dust.

The new legislation for laying hens in the European Union put a ban on conventional cages. Production systems must now provide the hens with access to a nest, a perch, and material for dust bathing. These requirements will improve the behavioral aspects of animal welfare. However, when hens are kept with access to litter, it is a concern that polluted air may become an increased threat to health and therefore also a welfare problem. This article reviews the literature regarding the health and welfare effects birds experience when exposed to barn dust. Dust is composed of inorganic and organic compounds, from the birds themselves as well as from feed, litter, and building materials. Dust may be a vector for microorganisms and toxins. In general, studies indicate that housing systems where laying hens have access to litter as aviaries and floor systems consistently have higher concentrations of suspended dust than caged hens with little (furnished cages) or no access to litter (conventional cages). The higher dust levels in aviaries and floor housing are also caused by increased bird activity in the non-cage systems. There are gaps in both the basic and applied knowledge of how birds react to dust and aerosol contaminants, i.e., what levels they find aversive and/or impair health. Nevertheless, high dust levels may compromise the health and welfare of both birds and their caretakers and the poor air quality often found in new poultry housing systems needs to be addressed. It is necessary to develop prophylactic measures and to refine the production systems in order to achieve the full welfare benefits of the cage ban.

Air Quality in Alternative Housing Systems may have an Impact on Laying Hen Welfare. Part II-Ammonia.

The EU ban on conventional barren cages for laying hens from 2012 has improved many aspects of laying hen welfare. The new housing systems allow for the expression of highly-motivated behaviors. However, the systems available for intensive large-scale egg production (e.g., aviaries, floor housing systems, furnished cages) may cause other welfare challenges. We have reviewed the literature regarding the health, behavior, production characteristics, and welfare of laying hens when exposed to ammonia in their housing environment. Concentrations of ammonia gas are commonly high in aviaries and floor housing systems in which manure is not regularly removed, whereas they are usually lower in furnished cages. High levels are found during the cold season when ventilation flow is often reduced. Ammonia is a pungent gas, and behavioral studies indicate chickens are averse to the gas. High concentrations of gaseous ammonia can have adverse health effects and, when very high, even influence production performance. The most profound effects seen are the occurrence of lesions in the respiratory tract and keratoconjunctivitis. There is also evidence that high ammonia concentrations predispose poultry to respiratory disease and secondary infections. We conclude that there are animal welfare challenges related to high ammonia levels, and that immediate actions are needed. Development of improved systems and management routines for manure removal and ventilation will be important for the reduction of ammonia levels and hence will contribute to safeguarding hen welfare.

Anticipatory and foraging behaviors in response to palatable food reward in chickens: effects of dopamine D2 receptor blockade and domestication.

Behaviors associated with anticipation and search for palatable food may provide information about dopaminergic reward processes and positive motivational affect in animals. The overall aim was to investigate the involvement of dopamine signaling in the regulation of cue-induced anticipation and search for palatable food reward in chicken, and whether domestication has affected expression of reward-related behaviors. The specific aims were to describe effects of mealworms (palatable food for hens) and haloperidol (a dopamine D2 antagonist) on foraging behaviors and cue-induced anticipatory behaviors in Red Junglefowl (RJF; the wild ancestor of modern laying hens) and a white layer hybrid (LSL). RJF (n=26) and LSL (n=20) were initially trained on a conditioning schedule to anticipate mealworms (unconditioned stimulus; US) 25s after exposure to a red light (conditioned stimulus; CS). For the experiment, hens received haloperidol or saline injections 30 min before exposure to one CS+US combination. Behavior was registered 10 min before CS and 10 min after US (foraging behaviors), and during the CS-US interval (anticipatory behaviors). Higher frequencies of CS-induced anticipatory head movements, faster approach to rewards, and higher frequency of foraging behaviors were found in LSL compared to RJF. Haloperidol suppressed CS-induced head movements in both breeds, and the frequency of foraging behaviors after reward delivery. The results support a role of dopamine signaling in the regulation of reward processes in chickens, and suggest that domestication has changed the threshold for perceiving food incentives and/or for expressing reward-related behaviors that may be indicative of positive motivational affect in hens.

Peripheral temperature drop in response to anticipation and consumption of a signaled palatable reward in laying hens (Gallus domesticus).

The present study describes effects of anticipation and consumption of a palatable reward on comb surface temperature. The purpose was to investigate temperature responses as a potential physiological indicator of positive emotional states in laying hens. A rise in body temperature in response to stimuli predictive of or during exposure to unpleasant events has been interpreted as evidence of emotions in mammals and avians. However, this phenomenon has so far only been studied during anticipation of or exposure to negative events; i.e., emotions of a negative valence. Infrared thermography was used to record potential alterations in comb surface temperature to a conditioned cue signaling a reward (mealworms) and during reward delivery. On average, comb temperature dropped 1.5 °C (95% CI: +/-1.2 °C) after exposure to CS and consumption of reward (p~0.0014) when initial comb temperature was above 30 °C. Such temperature drop indicates a peripheral vasoconstriction and has clear resemblances to emotional fever as seen during negative emotional states. Thus, we propose that a drop in peripheral temperature reflects emotional arousal more than emotional valence. Substantial temperature responses due to diet-induced thermogenesis were found, further emphasizing a cautious interpretation of altered comb temperature in studies of animal welfare.

Effects of haloperidol, a dopamine D2-like receptor antagonist, on reward-related behaviors in laying hens.

In order to investigate the involvement of dopaminergic transmission in the regulation of reward-related behaviors in laying hens, the effects of systemic injections of dopamine D2-like receptor antagonist haloperidol (0.3, 0.5, 1.0 and 2.0 mg/kg s.c.) 30 min prior to a conditioned cue signaling a reward were tested and compared to the effects of a saline injection. Head movements and latency to initiate display of anticipatory behavior were significantly affected by 0.3 and 0.5 mg/kg haloperidol, respectively. More hens were found lying down resting prior to the cue at 0.5 mg/kg and higher doses, and increased latency to peck at reward and shorter duration of anticipatory behavior was significant at 2.0 mg/kg. The findings are consistent with the involvement of dopamine in control of reward-related behaviors in laying hens. It is suggested that the lowest dose of haloperidol (0.3 mg/kg) affects reward-related behaviors, whereas the effects of higher doses of haloperidol could be confounded by sedative effects. A high inter- and intra observer agreement in the assessment of head movements together with their dopamine dependency further suggest that this behavior in classical conditioning paradigm represents an indicator of the state of the reward system in laying hens that can be assessed with good reliability.

Assessment of positive emotions in animals to improve their welfare.

It is now widely accepted that good welfare is not simply the absence of negative experiences, but rather is primarily the presence of positive experiences such as pleasure. However scientific investigation of positive emotions has long been neglected. This paper addresses two main issues: first, it reviews the current state of scientific knowledge that supports the existence of positive affective states in animals and, second, it suggests possible applications of this knowledge that may enhance quality of life under animal management conditions. In the first part of the paper, recent advances in psychology and neuroscience are reviewed to provide pragmatic frameworks based on cognitive processes (such as positive anticipation, contrast and controllability) for further investigations of positive emotions in animals. Thereafter, the neurobiological bases of positive emotions are highlighted in order to identify behavioral and physiological expressions of positive experiences in animals. Monitoring both the autonomic nervous system (via heart rate and its variability) and the immune system could offer relevant tools to better assess emotional states in animals, complementary to classical adrenocortical measures. In the second part of the paper, useful strategies for enhancing positive experiences (such as physical, social and cognitive enrichment or putative genetic selection) are outlined. Then this paper emphasizes practical applications for assessing and promoting positive emotions that may help in providing animals with a better quality of life. Play, affiliative behaviors and some vocalizations appear to be the most promising convenient indicators for assessing positive experiences in laboratory and farm animals under commercial conditions.

Comparison between microscopic and automated differential leukocyte counts in the silver fox (Vulpes vulpes) and the blue fox (Alopex lagopus).

Differential leukocyte (WBC) counts in blood from clinically healthy silver foxes (n=32) and blue foxes (n=37) obtained from an automated hematology analyzer (Technicon H*1 Hematology System) with canine software were compared with microscopic differential WBC counts (M-diff). There was good agreement between the automated differential cell count (A-diff) and the M-diff for neutrophil and lymphocyte percentages. The correlation was lower for monocyte percentages and variable for eosinophil percentages. There was no significant difference between the A-diff and M-diff in either fox species. The A-diff counts were very precise, and may be a good alternative to the traditional M-diff for screening populations of clinically healthy foxes or for studies on stress and animal welfare. Intercept values, however, indicated a constant bias that must be taken into account before interpreting results based on different methods of analysis