This happens in other chinese zoos as well. It is all day and animals are habituated to come near the bar whenever they see people, hoping for hand outs. There are signs for not feeding the animals, but that doesn't stop people from doing so. Very sad.
In all honesty, I don't remember there being much to keep visitors from stroking/feeding/molesting the animals on the Goat Hills at London. There were iron bars between caprids and visitors, but I really don't recall there being a safety barrier as such.
