Bushduikers yes, but the other ones are Bay, not red flanked duikers.they also have steenbuck in this enclosure. And they had also gerenuks in the same exhibit, but they all passed away.
I do hope though that the huge branches lying on the ground, are not still falling from the many trees we see. That could be disastrous for the hoof stock standing right beneath them.
The fencing in the back is part of the barrier theme of the exhibit area (simple ranch style) and all of the branches on the ground provides hiding places for all the small hoofstock in the enclosure.