My instant research into your question suggests that if they don't look like broad beans, they're having a laugh.
Horse bean,
Vicia faba var.
equina Pers., is a
variety recognized as an accepted name.
[1] This legume is very common in Southern European, Northern European, East Asian, Latin American and North African cuisines.
Horse bean
Beans.
If your horse's sheath is exceptionally dirty, periodically the smegma can mix with more dirt, sweat and mineral salts from the urine and form ābeansā. A bean looks and feels like a piece of hard gray bubble gum. Beans accumulate in the urethral fossa (this is the opening on the free end of the penis)