Nowadays, we view chicken mainly as a source of food. But back in Ancient Rome, they were considered sacred animals that had quite an impact on the decisions of Roman Empire rulers and generals.
Sacred chickens were part of the Augury practice, which included observing the behavior of birds in order to receive omens about future events. Augury was used in a wide range of situations but most notably in predicting the outcomes of battles.
Before engaging in battle, Roman generals would bring out sacred chickens and toss some seeds in front of them. If the chickens ate the seed, that was viewed as a good sign that the battle would be favorable for their army. If the chickens passed on the food, that was considered a bad omen.
One of the most famous uses of sacred chickens took place ahead of the naval Battle of Drepana between the Roman fleet commanded by Publius Claudius Pulcher and the Carthaginians.
According to an anecdote recorded by Roman historians, the Romans turned to sacred chickens to predict the outcome of the battle on their way to Drepana. The chickens refused food but Pulcher decided to disregard their warning. He commanded that they be thrown overboard, saying that they might be thirsty if they were not hungry.
It turned out the sacred chickens were right, since Carthaginians recorded a massive victory and caused Romans to refrain from naval battles for almost a decade.