The zoo has certain times that they will permit feeding only certain animals. You can only feed them what they sell ($5 for 3 romaine lettuce leaves). Feeding time is strictly monitored. You get the leaves just before you are allowed in the raised & gated area, you can't touch or tease the animals, and you need to move along after you have fed them so another person has a chance.
We've never been lucky enough to be there at the right time for this. It was absolutely perfect! Ezra loves the zoo and giraffes were his first favorite animal. He did great!!