Abstract: Worm-running is behaviour in which a chick runs carrying a worm-like object while flock mates follow and attempt to grab the object from its beak. We hypothesised that social ranks based on worm-running frequency are stable over time and are positively correlated with social ranks based on success in aggressive interactions when older. At 8-12 days of age, we scored worm-running in 17 groups of 12 female White Leghorn chicks during three 10-min tests. Based on instantaneous scans at 5-s intervals, the bird carrying the `worm' most often was placed in rank one and so on down the rank order. These tests were repeated at 68-70 days of age. An aggression index for each bird was calculated as the number of aggressive acts given, divided by the number given and received, during three 1-h observation periods when the birds were 68-70 days. Ranks obtained in worm-running tests were positively correlated over the two age periods (P<0.05) but were not correlated with ranks based on the aggression index (P>0.05). Our results indicate that worm-running ranks are not predictive of success in aggressive interactions. Instead, worm-running fits some criteria for play.

Abstract: In a 2 x 3 factorial experiment we examined the effect of exercise (no exercise/daily exercise) and paddock size (small: 150 m2, medium: 300 m2 and large: 450 m2) on the behaviour of horses. In both these treatment periods nine (three cold blood and six warm blood) adult horses were exposed to all the three paddock size treatments for 2 h daily, for 1 week in each paddock size, and the order of paddock size treatments were rotated systematically. In between turnout in paddocks the horses were all housed in tie stalls. In the non-exercise period the horses walked significantly more, they travelled a longer distance, explored more and stood more alert, than in the period with exercise. The horses stood less passively in the large paddock compared to the medium and the small paddock, and they also travelled a longer distance in the larger paddock sizes. At days with heavy rain and wind, the horses were more restless and walked significantly more than in warmer weather. In conclusion; daily exercise significantly reduced the general activity in the paddocks. Increasing the paddock size to 450 m2, increased the time spent eating grass from under the fence and decreased the time spent standing passively.

Abstract: We investigated 71 horses at five stud farms. Their breeds were Thoroughbred (n = 48), Anglo-Arab (n = 7), Thoroughbred mixed breed (n = 5), Appaloosa (n = 3), Selle Francais (n = 2), Dutch Warmblood, Haflinger, Pinto, Quarter Horse and Westfalen (n = 1, respectively), and one horse's breed was not known, but was a heavy horse. Their genders were stallion (n = 5), gelding (n = 41) and female (n = 25). Their ages ranged from 4 to 24 and the average was 11.1 +/- 5.3 (S.D.). The horses' behaviour was twice observed for 2 h both before and after feeding, using a scan sampling technique at 2 min intervals. We investigated the relationship between management factors, age, sex, breed and behavioural patterns of stabled horses, and the occurrence of weaving by a least-squares analysis of variance, a correlation analysis, Chi-square test and an analysis of behavioural sequences. Thoroughbred horses displayed weaving more than other breeds (P < 0.01) and horses in box stalls which were face to face with each other displayed weaving more than those in box stalls which were formed in a line (P < 0.01). The time budget of weaving correlated negatively with the amount of hay-cube fed (kg/day) (P < 0.05) and time budgets of drinking, bedding investigation, looking and coprophagia (P < 0.01, respectively). From the analysis of behavioural sequences, weaving followed resting (P < 0.01), looking (P < 0.01) and pawing (P < 0.05), and was followed by them (P < 0.01, P < 0.01 and P < 0.05, respectively). The least-squares analysis of variance revealed that Thoroughbred horses investigated the bedding more than other breeds (P < 0.05), horses that are usually in contact with `mainly familiar people' investigated the bedding significantly less than those usually in contact with `people including strangers' (P < 0.05), and horses in box stalls which were face to face with each other tended to investigate the bedding more than those in box stalls which were formed in a line. The time spent feeding was related to food type (min/kg), and tended to be negatively correlated with the time budget of bedding investigation behaviour. These results indicate that weaving in horses is affected by breed, stable design, feed type, and other behavioural traits.

Abstract: Processed feed for stabled horses is usually presented in buckets or mangers, and is easily and rapidly consumed. Foraging devices based on the Edinburgh foodball can be used to provide part of the ration. Current designs are all placed on the floor, raising concerns regarding ingestion of foreign materials along with the dispensed food. Alternative devices were evaluated, when presented within suitable, clean containers to prolong food-handling times but avoid such issues. In four Latin square designed replicated trials we investigated behaviour of 12 stabled horses with three foraging devices. These were separately presented for 5 min, varied in sensory complexity (round, square, polyhedral) and contained 500 g high fibre pellets. In Trials 1 and 2 six geldings were presented with devices in buckets then mangers. All individuals foraged successfully from at least one device and behaviour was compared. However, all individuals exhibited some frustration while using the devices (either pawing or biting them). Horses frequently removed the devices from the buckets in Trial 1 terminating these sessions. In Trial 2 mean device foraging duration was ranked polyhedral > round > square. Mean pawing rate in Trial 2 was calculated for horses (frequency of pawing per individual/summed duration manipulation and foraging) and was highest with square (0.11, npawers = 6). In Trial 3 six stabled mares were presented with the same foraging devices in mangers. Mean foraging duration with devices again ranked polyhedral > round > square. Mean pawing rate was highest with round device (0.08, npawers = 4). Trial 4 investigated behaviour of six horses when devices initially containing five high fibre pellets became empty. Mean foraging duration with devices ranked round > polyhedral > square. Mean pawing rate was highest with square device (0.11, npawers = 4). All horses foraged successfully from at least one foraging device in buckets and mangers. Devices met initial objectives but the unpredictability of reward suggests a source of frustration and warrants further investigation.

Abstract: The evaluation of important parameters for measuring the horses’ cognitive capacities is one of the central topics of the equine behaviour team at Nürtingen-Geislingen University. Social complexity has been said to be one of the settings in which needs for cognitive capacities arise in animals. A variety of studies throughout the last two decades proved the horses’ social complexity to be far more elaborate than previously assumed. Horses form social bonds for the protection of offspring, intervene in encounters of others, identify group mates individually and easily orientate in a fission fusion society.
In such socially complex societies, animals will benefit from learning socially. In many bird and primate species the degree of social complexity correlates nicely with the species abilities for social learning. Social learning was, therefore, argued to be an indicator for elaborate mental capacities in animals. We were delighted to prove that horses actually copy social behaviour and techniques for operating a feeding apparatus from older and higher ranking group members. In a recent study we found young horses, at the age of 3 to 12, to copy the operation of a feeding apparatus from a human demonstrator. Social learning seems to work nicely in horses when the social background of the animals is considered.
The degree to which individual animals adapt to changes in their social or physical environment by finding innovative solution appears to be the other side of the coin, of whether animals adjust to challenges by social learning. It is not very astonishing, that along with the animals’ social complexity and their ability to learn socially also the degree to which they show innovative behaviour was claimed to be one of the most important demonstrations of advanced cognitive capacities. In a recent approach, we started to ask horse owners and horse keepers in many countries to tell us about unusual behaviour of their horses via a web site (http://innovative-behaviour.org). To date, we received 204 cases of innovative behaviour descriptions from which six cases were clear examples of tool use or borderline tool use. We categorized the innovative behaviours into the classes, a) innovations to gain food, b) innovations to gain freedom, c) social innovations, d) innovations to increase maintenance, and e) innovations that could not be clearly assigned to a category. About 20% of the innovative horses showed more than one innovation. These animals could be termed “true innovators”. Again, young horses were more innovative than older ones with the age group 5 – 9 showing the highest number of innovative behaviour descriptions.
In a nutshell, the horses’ cognitive capacities appear to be underestimated throughout the last decades. The horses’ social complexity is far more elaborate than previously assumed, horses learn socially from conspecific and humans, some of them demonstrate innovative behaviour adaptations to their environment and even simple forms of tool use.