Teaching farm kids about sex and reproduction

My kids have started asking about chickens being able to reproduce. They are starting to understand how we need a rooster for baby chicks but they are now curious about other livestock. And I want them to know the truth.<br><br>My kids are 4, 6, 8, and 11. What is the best way to explain how different animals reproduce? We are currently doing chickens, pigs, and cattle.