I didn't see where the toad came from as it already had it when I saw it. I was stood watching it for a while though, don't tend to see them doing much other than jumping about.
I spoke to one of the hornbill keepers a few months after this was taken and mentioned that we'd seen him with a toad in his beak. I was told that he must have caught it himself as it wouldn't have been fed to him by his keepers!