I recently got 2 miniature donkeys. A 7 month old jack, who will be gelded as soon as he drops, and a 4 year old Jenny. My Jenny is in heat and I caught my little guy trying to mount her. He's quite a bit smaller, so I don't think he can reach, but she stood still for him. What are the chances he is fertile at his age, even though he hasn't dropped? I'm not looking to have a baby.