Updated: Mar 23
Resource guarding is the reason behind many (unfortunately common) agonistic social behaviours we see in domestic horses. Management often causes limited (or the perception of limited) resources, which distorts natural social feeding behaviour (Goodwin, 1999).
Resource guarding: “The use of avoidance, threatening, or aggressive behaviors by an [animal] to retain control of resources in the presence of another animal” - Jacobs et al (2018).
A resource refers to something the animal perceives as valuable, often something needed to survive (ie food, water, etc). For instance, a large group of horses having to share one round bale, or one water trough.
In their natural setting, horses are not generally territorial or agnostic to each other. When a resource is in limited supply, horses in natural conditions don’t often become aggressive or protective of it. Horses avoid direct confrontation, and as food is often easily accessed in their natural environment, tend to spread out rather than fight for it (Fraser, 2017; Furiex et al, 2012; Kruger and Flaugher, 2008).
So, when food is limited to one location or limited access, or set to specific meal feeding times, this creates a pressure around the resource that the natural horse would not often experience.
Lack of foraging opportunities and high density increases agonistic interactions in social groups (Furiex et al, 2012).
Horses who are not stressed around food may also begin to associate meals or access to foods as stressful if their environment becomes stressful for them (ie, a pasture mate who resource guards the sole water source), so optimal management is key to minimize stress around feeding.
Low levels of social injuries reported in domestic horses with management conditions that are semi-natural (Furiex et al, 2012). Resource guarding behaviour reflects a need for a management change - the good news is that strategic feeding management can help reduce resource guarding!
Strategies to Reduce Resource Guarding in Horses
Forage & water available at all times
Increase number of feeding sites
Increasing space between feeding sites
Keep horses with stable & compatible social groups
Avoid overcrowded fields
When adequate space and stable social groups are provided, horses avoid confrontation (Goodwin, 1999). Furiex et al (2012) found that increasing the number and space between feeding stations (at least one per horse) not only reduces agonistic behaviours, but also increases positive social behavours (allogrooming, more social cohesion, and less aggression). Optimizing your social feeding management can not only reduce both your horse's stress and risk for injury, but can also improve social interactions between horses.
Jacobs, JA., Coe, JB., Widowski, TM., Pearl, Dl., Niel, L. 2018. Defining and Clarifying the Terms Canine Possessive Aggression and Resource Guarding: A Study of Expert Opinion. Frontiers Vet Sci 5: 115
Kruger, K., Flaugher, B. 2008. Social feeding decisions in horses (Equus caballus). Behavioural Processes 78(2008): 76-83.
Goodwin, D. 1999. The importance of ethology in understanding the behaviour of the horse. Equine Veterinary Journal 31(s28): 15-19.
Furiex, C., Bourjade, M., Henry, S., Sankey, C., Hausberger, M. 2012. Exploring aggression regulation in managed groups of horses Equus caballus. Applied Animal Behaviour Science 138(2012): 216-228.
Fraser, 2017: Food Aggressive Horses. https://www.equinebehaviorist.ca/post/2017/12/07/food-aggressive-horses