Aggression is a natural and sometimes necessary trait for horses, particularly those living in a domestic setting. Food aggression comes from a basic desire to protect resources, and therefore although common in the domestic setting, is not seen in wild herds where resources are plentiful (1).
Different species hold different resources in high esteem. Horses require space for grazing, exploration, play, body care and vascularisation, as well as a variety of different herbage and browsing, water, shelter, shade, and mares for reproduction (2) .
Resource Holding Potential refers to an evolutionary strategy that has stood the test of time. In the wild, each horse understands what resources the other members of the herd have ‘first refusal’ to, eliminating the need to fight. This is a far more accurate way to describe the social hierarchy of a mammal, differing to the commonly believed notion of ‘pecking order’ only observed in birds. Resource Holding Potential status differs for different resources and between individuals.
When resources become scarce or poor quality, an animal becomes ill or there is a change in group structure, this strategy is de-stabilised and the individual becomes motivated to ‘hold on to what he has got’ protecting the limited resources available, it is a simple survival instinct.
In a typical livery yard where herds are not permanent, grazing space is small, feeds are not regular, stables are used daily and turnout time short, horses quickly learn to protect the limited resources available to them, whether it is simply not being caught or adopting aggressive behaviour to handlers or other horses.
Effective treatment will depend on the severity of the problem, how long the behaviour has gone on for and the individual, however in my experience, allowing for more natural behaviours and providing additional resources resolves approximately 70% of the problem within a couple of days.
If the horse is allowed to be turned out for 24 hours a day, put in an area with ample grazing, foraging and browsing, in a stable herd, the results will come sooner. However if the horse really does have to be stabled, simple enrichment ideas go a long way. Here are a few to try…
- Hang tree branches in a corner of the stable, and add licks, carrots, slices of apple.
- Attach a door mat to the shed and a sturdy fence post or tree to enable self-grooming maintenance.
- Provide different varieties of hay and herbage, scattered loose on the floor rather than in a hay net or feed bowl.
- Allow straw bedding for its deep bed, texture and thermal properties.
- Produce a new variety of vegetable for each day of the week.
After relieving this initial frustration, you can begin to work on the other 30% of the problem. This part deals with the deeply learnt side of this behaviour, simply learning that this strategy works!
To ‘undo’ this learning (3) I would advise that you speak with a qualified animal behaviourist who uses only positive reinforcement, as this part of the solution requires a detailed understanding of the individual and his or her background.
Anyway I hope this helps anyone who needs it, for more specific advice just ask!
(1) Maynard Smith, J. (1982) Evolution and the Theory of Games, Cambridge University Press, United Kingdom
(2) McDonnell, S. (2003) A Practical Field Guide to Horse Behaviour: The Equid Ethogram, The Blood Horse Inc., United States
(3) Beck, A. (1976) Cognitive Therapy and the Emotional Disorders, International Universities Press, United States