Watchful:

I had driven fertilizer spikes around our one apple tree and either the dogs or squirrels dug one up and our new family member found the spike and before I could get to him he had ate a part of it. 
I did a search on what the ingredients were and fortunately none were toxic but when he passes the pieces he is going to have a challenge. Those spikes have to be driven into the ground and getting one back out isn't easy. It is over eight hours and he has had no ill effects so far but we are watching him closely.