A vertical nipple might actually work well, but not the horizontal ones, he could tap the pin with that bottom beak and water would run right into his mouth.Personally, I think nipple watering would be hard for him to navigate. He would have to peck it in order to get any water - he only has a bottom beak, so I am unsure how he would peck and catch water at the same time.
Very odd situation.
As there was no bleeding, unless I missed that part, I wouldn't treat it like a wound.
Wonder of there was some kind of injury that caused the beak to crack and 'die' then break off?
Sure hope it grows back, but I've got my doubt.
Sweet thing is still going as far as I know. I hope you find it inspiring.
I suppose it will remain a mystery.