Animals should be given the opportunity to perform behaviours that they are motivated to show if we are to maximise their welfare. Research studies into motivation and appropriate methods of studying it are therefore important. Different factors may need to be taken into consideration depending on the form of the behaviour being studied. Certain commodities, such as a perch for night-time roosting, have a value only if the animal is given full access to them until it has completed the behaviour. For other commodities, such as food and water, the amount can be varied along a continuous scale without affecting the animals’ demand for that resource. The commonly used operant techniques generating demand curves are based on the assumption that demand is not affected by the size of the reward (ie how much of the commodity the animal gains access to). As a consequence, these techniques are appropriate only for assessing motivation for resources of which the size can be varied. Resources of the ‘all-or-none’ type, on the other hand, require a different approach. We discuss different adaptations of the push-door technique as a measure of motivation, and we present results that validate a version with fixed, individually adapted levels of resistance. The method was validated using laying hens (Gallus gallus domesticus) tested at different levels of food deprivation and exposed to two series of increasing door resistances. The results show that the level of food-deprivation affects the amount of resistance that is overcome. We conclude that this method could be used to study hens’ motivation for commodities of the ‘all-or-none’ type.

Free-living hens perch on branches in trees and domestic hens (Gallus gallus domesticus) show signs of unrest if they cannot reach a perch, suggesting that night-time perching is a behaviour that hens are motivated to perform. This motivation was quantified in two experiments using a weighted push-door that hens had to push open in order to gain access to a perch. First, the motivation of individual birds to perch, and second, the effect of a companion bird on perching motivation, were measured. Eight adult laying hens (Lohmann Selected Leghorn) were trained to push through the door at increasing resistances, and the individual capacity of each hen was determined. Hens were then tested once per day, at lights-off in a test pen where pushing through the push-door gave access to the resource. Two consecutive series of increasing resistances were used in the experiment: 25, 50, 75 and 100 per cent of each bird's maximum capacity. In the first experiment, the resources offered were either a perch (treatment) or a ‘sham perch’ that could not be used for perching (control). Hens opened significantly heavier doors in order to gain access to a perch than to gain access to the sham perch. In the second experiment, pushing through the door gave access either to a perch with a companion hen already perching on it (treatment) or to a perch and a companion hen roosting on the floor (control). In this comparison, four of the hens did not push through the door, probably because of aggressive interactions with the companion, and no significant differences between treatments were found. We conclude that hens are motivated to use a perch for night-time roosting and that they should be housed in systems with perches.

The ability of dairy cows to discriminate between floors with a smooth epoxy resin surface or with surface-applied bauxite aggregates of mean diameters 0.5 mm, 1.2 mm or 2.5 mm (having coefficients of static friction of 0.35, 0.42, 0.49 and 0.74, respectively) was recorded when they were offered the opportunity to walk down paired floor surfaces to receive a food reward. Following training, one half of the cows were rewarded when they selected the floor with the greater friction and the other half were rewarded when they selected the floor with the least friction. The cows were able to distinguish between the different floor surfaces — even between surfaces with 0.5 mm and 1.2 mm aggregates, which humans found difficult to distinguish. Eight similar cows were then offered a choice of walking down passageways of paired floors with an equal reward at the end of each passageway. There were no consistent preferences for floor type, and when the reward was offered only on the side least favoured by each cow in the initial test, the random pattern of selection was still evident. A final choice test offered the cows the opportunity to traverse passageways of either wet concrete or concrete covered with excreta. All cows avoided the passageway with excreta completely, even when the reward was increased in this passageway and removed from the wet concrete passageway. This avoidance was attributed to the cows’ lack of contact with slurry, as they were at pasture for most of the day, in contrast to the cows used in previous work, which were housed in buildings with passageways covered in excreta and showed little avoidance behaviour of such passageways.

Assessing the experience of pain in animals is a difficult task, yet one that is important in animal welfare research. Some approaches to pain assessment in animals are reviewed here. General qualities of pain scales and specific parameters suitable for clinical and experimental pain assessments are discussed. It is argued that pain assessment will progress through an integration of objective and subjective observations of behaviour coupled with multiple measures in various other areas. Such multidimensional pain scales allow an adequate characterisation of the complexity of an individual animal's pain experience to be made. This knowledge improves the recognition and treatment of pain and will allow informed moral debate on the acceptability of practices such as castration and tail-docking of lambs.

The purpose of this experiment was to provide information relevant to the current debate concerning the optimisation of terminal stocking density for commercial broiler production. In a modern, controlled-environment house with 24 floor pens (each 11.4 m2), 4020 day-old broilers (Ross 308) were allocated to three terminal (42 days) stocking densities (28, 34 and 40 kg m-2) x two sexes x four replicates, according to a randomised block design. Group sizes varied from 130 to 208. Husbandry conditions were in accordance with normal commercial practice. Performance and behaviour were measured systematically during each of the six weeks of life, and additional measurements were made of leg health and litter condition. Data were analysed using ANOVA to determine the effects of stocking density, sex and age. The realised mean terminal stocking densities were 28.2, 33.5 and 38.5 kg m2. The main significant effects of stocking density treatment were a linear decline in food intake with increasing density during week six (the final week), and a reduced proportion of time spent panting deeply during weeks five and six at the lowest density. Increased (shallow and deep) panting shown by females in weeks two to five suggests that if thermal discomfort becomes a problem at higher stocking densities later in the growing period, it may do so earlier in females. There was no conclusive evidence from this study that broiler welfare is compromised any more at 40 than at 34 kg m−2. The fact that the proportion of time spent panting deeply in week six was considerably lower at 28 kg m2 than at 34 and 40 kg m−2 suggests that thermal comfort (and hence welfare) at this age may be improved at densities of less than 34 kg m−2. However, the significant effects of age, age x density, and age x sex on time spent panting deeply suggest that the age at slaughter and the sex of birds in single-sex flocks should be taken into account in future considerations of optimal maximum terminal stocking density.

The aim of this study was to examine the effects of roughage and shelter on certain welfare indicators in growing pigs that have access to ample straw and space. The effects of the two treatments were evaluated both by recording the pigs’ use of the various areas of the pen and by measuring the frequency of two specific behaviours, ‘aggression’ and ‘play’, that are considered to be significant indicators of welfare in pigs. Seven replicates were used, each involving 96 pigs. The pigs were randomly allocated to eight experimental pens at 10 weeks of age, and were observed from 13 to 22 weeks of age. The two treatments, roughage and shelter, were distributed according to a 2 x 2 design in the pigs’ outdoor runs, four of which were located on each side of the barn (north side versus south side). The pigs spent most of their time in the straw-provided areas, and the frequency of their aggressive behaviour was also the highest in these areas, suggesting that these locations were the most attractive to the pigs. The pigs with access to roughage showed a lower frequency of aggression (P < 0.05) and spent more time in the outdoor area where the roughage was placed than those pigs with no access to roughage (P < 0.05). No other effects of treatment were found on the length of time spent in the different pen locations. Play frequency decreased with age (P < 0.05) and with increasing temperature (P < 0.01). Moreover, when housed on the south side of the building, the pigs with access to shelter played more than those without (2.0 versus 1.0 events per hour [SE = 0.3]; P < 0.05); this suggests that the opportunity to regulate the body temperature by use of shade results in improved welfare. In conclusion, the pigs’ behaviour indicated that their welfare was improved by free access to roughage and shelter.

A case study is described in which a high incidence of lameness in broiler chickens (Gallus gallus domesticus) is associated with rearing to 84 days of age; broilers are normally slaughtered at less than 50 days of age. A sample of 185 birds was scored for walking ability, and 24 birds from this group were assessed for dehydration by measuring plasma osmolality. The proportion of the group having gait abnormalities was compared with that recorded during a recent survey of Danish flocks and was found to be higher. A relationship is established between the degree of gait impairment and the level of dehydration. The degree of dehydration is related to the findings for plasma osmolality from previous research, and the results indicate that some of the birds in this case may have been deprived of access to water for periods in excess of 60 hours.

Although it is known that many birds possess ultraviolet (UV)-sensitive vision, most commercially housed poultry species, as well as species held in zoos, laboratories, or bred for show, are maintained under lighting that is deficient in UV wavelengths compared with normal daylight. UV-sensitive vision has been shown to be important in both foraging and mate-choice decisions. UV-poor conditions, in which information in this waveband is eliminated, could, therefore, present an important welfare issue. Eight European starlings were given a series of preference tests (eight hours per trial, for six days), in which they could choose to feed in one of four channels. Four experimental trials were carried out, during which the channels were covered in either UV-transmitting (UV+) or UV-blocking (UV-) filters, to determine whether birds had an initial preference for feeding in UV-rich environments and whether there was any change in their preference over time. There was an initial preference for the UV+ environment, but this preference declined very rapidly with familiarity, and was absent by the final trial. These results imply that starlings can rapidly adjust their feeding behaviour if faced with unfamiliar light environments and that any initial behavioural changes attributable to UV-deficient environments may be short-lived. However, further work is necessary to establish whether these adjustments occur across a range of species and contexts before any welfare concerns can be ruled out.

The effect of transport on core and peripheral body temperatures and heart rate was assessed in ten 18-month-old Coopworth ewes (Ovis aries) Manual recordings of core (rectal) temperatures were obtained, and automated logging of peripheral (external auditory canal and pinna) temperatures and heart rate was carried out on the day prior to (day 1) and during (day 2) a standardised transport procedure. Transport produced a significant increase in the rectal temperature, which declined following unloading. Peripheral measures of body temperature also exhibited changes with transport. However, both ear-canal and pinna temperatures declined during actual transport, reflecting to some extent the decline in ambient temperatures recorded externally by sensors on the ear tags of the animals. Peripheral measurement of temperature, particularly at the readily accessible ear canal, may offer potential as a technique for the long-term monitoring of thermal responses to stress. However, further research is required into the potentially confounding effects of ambient temperature and wind chill factors.