Horses, ponies and donkeys are all social animals but there are subtle species-specific differences in their behaviour. For details of donkey behaviour and how this differs from horse/pony behaviour see How to understand donkey behaviour | The Donkey Sanctuary.
Horses naturally live in either family groups (often referred to as harems, consisting of a stallion, a few mares and their offspring) or bachelor groups (consisting of colts and stallions that do not have mares). They are a prey species where safety in numbers is very important, and their first line of defence from predators is to flee. They are herbivorous and adapted to thrive on low nutrient, high forage diets. They are trickle feeders (eating little and often) that walk steadily while grazing. Free-living horses often travel long distances to access resources such as food, water and shelter. These natural behaviour patterns provide information about the behavioural needs of the domestic horse. Their innate need for company, forage and movement should be considered when managing domestic horses. So, the Three Fs (friends, forage and freedom).
For information about what horses need and their natural behaviour see: bluecross.org.uk/pet-advice/what-horses-need-and-natural-behaviour
Further information about the behavioural needs of horses, ponies, donkeys and their hybrids can be found in the Code of practice for the welfare of horses, ponies, donkeys and their hybrids.
It is important to monitor the behaviour of individual animals throughout their lives as a means of assessing their well-being. Although specific behavioural patterns will vary according to factors such as workload, housing and social grouping, behavioural changes can be indicative of underlying health issues or result from problems that the animal may have in coping with other aspects of its life. Some behavioural signs to look for are included in the RSPCA Guide to conducting an equine health and welfare check. ‘Understanding your horse’s behaviour’ is a simple guide to recognising basic behavioural signs of how the horse is feeling.
If you have concerns about your horse’s behaviour you should consult your vet to ensure it is not a health-related issue. If you need to consult a behavioural expert, there is a register of Animal Behaviour and Training Council (ABTC) approved practitioners to be found at: abtc.org.uk/