Having stayed there twice, I can tell you that the animals are out all day long.
Having said that, however, the animals are always roaming and if it is too hot they may be hanging out off in a shady spot. It is really hit or miss as to where or what kind of animals you may see at any given time during the day. We were able to see different animals in different public areas at all different times of the day. Sometimes we saw 1 or 2 , other times many. Either way it is still a very enjoyable experience.