Ours ate macadamias too. We didn’t feed them to him, we’d just left a bucket of them outside. One evening his rear legs gave way. As if he had a tick. Couldn’t find a tick, though. By the time we got to the 24hr vet, he was staggering around again, so not a tick, the girl on reception suggested macadamias and the light went on! Anyway, he fully recovered (she said he would, not a problem so long as they stop eating them) and at least we knew his teeth were strong.
