Aggressive males.

[LordFokas]

Most males (Cocks, Bulls, and Rams) will be aggressive towards the player.

Cocks should even be aggressive against other cocks, fighting each other to death.
This should be a slow process.

Cocks attacking a player should cease all aggressiveness when the player strikes back, not attacking any other players for a set duration. They should also get a small regen bonus when slapped so that players don't accidentally kill them.