The deer would eat grain right out of your hands. I don't mean to sound morbid, but the only deer I have ever touched were dead ones after I shot them during hunting season. I have always had a lot of respect for deer, so it was a real treat to get to pet a live one.
Bear world is a cool place, and ironically, the grown man was the one who seemed to enjoy the petting zoo far more than any of the kids that day. Go figure.