It took me all my drive to think of an animal to answer your question. I guess for our animals the most difficult can be the royal python snakes who sometimes don’t want to eat and can go weeks without feeding. That can be frustrating. In terms of danger of feeding would be Santa’s reindeer. I will explain more in my post later about them but they are very dangerous animals and we work in twos with them! Always got to keep an eye on what they are doing otherwise you can end up in a lot of trouble! I will have to check Hogle Zoo out!