What do they feed Lions at the Wellington Zoo?

At the Wellington Zoo they feed the Lions, horse with added horse shoe for extra iron supplement. I actually took this photo myself on a trip to the Zoo in 2006. I love the shot and the suggestiveness of it. Whilst I know it was taken in a closed environ where a dead horse was fed to the Lions, in the absense of that knowledge, you could think of any horrific scenario that left a horse leg on a rock....
The Wellington Zoo is acutally a pretty decent zoo, very family friendly and the animals are well treated etc. Unlike the Phuket Zoo, where I visited last year. If the photos suggest I was having a good time I was, but on reflection it made me sad.

Check out some pictures of Lions feeding in the wild.