"Maybe some people don't know that it can sometimes be beneficial to divide the cows. The probability of an attack increases stepwise as the number of cows approaches a single unit.
For example, the 22nd cow has a 35% chance of killing 3 enemies.
But if you divide them into groups of 11, each group has a 30% chance of killing 2 enemies. This means there's a chance to kill 4 enemies at once, which wasn't possible with a single herd of cows!"