Hormonal imbalances can cause mood swings, hypersensitivity and poor performance
It should always be remembered that mares are ´entire´ horses, and as such can be prone to hormonal imbalances. These can be seen in a variety of ways, including poor perfomance, reduced movement, hypersensitivity to being touched and becoming cold-backed. However, the most common problem is mood swings when even the sweetest mare can become unpredictable and aggressive.
These problems can be addressed with hormonal additives but many are far from ideal and are not suitable for long term use, creating a need for nutritional approaches. In the wild the mare could supplement her own diet with herbs specific for her needs, but this is not possible with modern pasture.