Chaste tree has been traditionally used for moodiness in mares. It is a natural hormone re-balancer and can also be used for cushings disease. Also useful in stallions or geldings who are being aggressive.
"For two years I've used Chasteberry on my mare Ali for her Cushing's and it's worked wonders. She's alert, loads of energy (she's 25 and runs around like a 5 year old), sheds out nicely every spring and not to mention the improvement of her feet (she had Laminitis, slightly turned years ago). She has the Cushing's belly but I think I can live with that. Just thought you might be interested."