I just got a two year old billy from a neighbor. I initially got the billy to keep one of my whether (3 month old) goats company. The new goat is a pygmy as well. As soon I as got home, I put the new goat in the corral with the mule to keep the new goat separate from the whether for a few days. My mule is broke to ride, and has not been aggressive to other animals. The problem is that the mule chased the new billy, trampled him a little and even tried to kick him. I now have the two separate. Does anyone know what I should do?