Equine herd dynamics

feral-horses-956679_960_720I recently replied to a forum question and have been asked to publish it as a blog to a wider audience. The question provided this information:
The horse had been with same caregiver for 22 years, since a foal. Described as “a dominant horse but in a good way. A kind leader. He only has to flick his ears and horses move out of his way. Always the first at the gate. And just generally in charge. Moved yards over the years and always ended up running the group.” Following the most recent move to a new yard his caregiver reported that she was surprised to find him being chased off the food she offered him, and keeping away from any threatening behaviour. The yard owner told her he was not being chased around but was definitely keeping a distance and cantering off if one of the other horses came near. She was surprised that after careful introductions he was not as much of a boss he has been, and asked what might be happening.

I replied:
Your horse is very lucky to have had you as his sole caregiver since foalhood. A few points spring to mind from your post. Yes the flicking ears will keep other horses away in situations where all the horses know each other and understand the individual and group communication; however unlike chickens (it was early studies of dominance in chickens that coined the phrase “pecking order”), the social operation of groups of horses is based on affiliative and co-operative behaviour rather than dominance; their social structure is complex, nuanced and fluid, based on the value, availability and motivation to obtain available resources that are biologically and socially important to the horse. The structure is more like a complex web than a linear hierarchy, so it’s not particularly helpful to try to understand how horse groups operate from a perspective of dominance.

In evolutionary terms, it doesn’t make sense for horses always to be having arguments about access to resources, although on many yards it can seem as if that is the case. As an organism the horse needs to expend its energy moving to safe places, and finding food, water, shelter and shade to survive and reproduce the next generation. Horses haven’t evolved to have energy spare to fight all the time about who gets which choice piece of hay. That’s why you’ll find that where horses live in a settled group they have established extremely subtle communication signals like you’ve seen with your horse’s ear flick. It’s also why horses that move yards, or are turned out with different horses, often seem to have more “arguments” (resource holding contests, which can be small and low key, through to very aggressive), because the group is not settled or consistent, making it harder to learn the communication signals that each horse uses and requiring frequent re-contesting of various resources including piles of hay, and access to the gate which is often a predictor of access to a tasty bucket of food. Even when horses are stabled at night and turned out again together the next day this can create new resource holding contests once the group is back together, because it’s not natural for a group of horses to be separated, so if that happens they need to re-test who is allowed access to which resources each time the group reconvenes.

The measure of the ability of one horse to acquire and hold a specific resource, or to move another horse off a desired resource, be that hay, water, the best sun-bathing spot, the best rolling patch, is referred to as resource holding potential (RHP). RHP is understood in relation to individual resources and individual horses; different resources can take on different values at different times, for example shade isn’t very important on a cold, cloudy day.

Horses don’t have a linear hierarchy, with horse A being at the top and horse Z at the bottom. Instead it is more like a complex web, where different situations have different value for each individual horse based on their past experiences. For example, if horse A has had a history of insufficient forage they might move other horses off forage, and the other horses defer as they have learnt that that resource is less important to them than it is to horse A. However, horse B might highly value shade so will be first in line for that resource over horse A. So understanding horse behaviour in that way can help us to work out the causes of their behaviour.

You can find out more about the structure of group relationships in these articles published by the Equine Behaviour and Training Association (EBTA):

Regarding your own horse, it’s interesting that despite several yard changes he has always ended up running the group. Without more information it’s hard to say why this might be, but some of the factors that influence high or low resource holding potential are laid down at a very early age including health status, how they were weaned, the emotional and health state of the mother, very early experiences, stress levels, relationships with other horses in the group, the type of activities they do with their owner, training methods, any specific and salient learning experiences…. These factors plus the health and emotional states of the other individuals in the group, and the different environments on different yards, will all have an effect.

An individual horse’s RHP can also be affected by any recent illness or injury, resource availability and group management. In a settled herd the horses all ‘work out’ access to resources between them and do not need to routinely re-affirm those relationships. But when the herd changes there will be some contests. Perhaps the histories of the new herd-mates means that resources are more important to them than some of your horse’s previous herd mates. Part of the jigsaw is the magnanimity or otherwise of group members and that is also to do with their willingness to contest a resource. At 22 your horse is not that old but certain age related conditions could be starting that might have lowered his RHP, coupled perhaps with the anxiety that comes with attempting to establish the social structure when he is the new horse, unfamiliar with the other horses and the daily routines of the yard.

As you can appreciate without a full understanding of the history of all the horses in the new herd it is difficult to suggest a reason for the behaviour. In terms of solutions you might be looking at good management including deterring congregation around gateways where he could get injured, and if he is still very unsettled then thinking about systematically re-introducing him using the recognised practice of dividing the field and then dividing one part of it again (so you end up with three sections to the field), taking a middle ranking horse (obviously in general terms having said all of the above about how complex the social structure is!) and grazing them in the two smaller sections (one in each smaller section). Eventually over a few days you will see that they start to graze closer to each other and may even start to chat and mutually groom over the fence. When you have seen them doing this for 2 or 3 days take away the temporary fence that divides them. Keep them together but separate from the rest of the herd for a few days and then take away the final section of temporary fence so that the new pair are now integrated into the existing herd.

I hope that helps and I hope your boy is more settled now after more time in the new herd; but if you are concerned then it’s always possible to re-introduce him along the lines explained above.

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