Found two on the ground. About three weeks apart. The last one was about 4 days ago.
UPDATE 2019/10/17: We find them all over the place now. Not so rare anymore.
In my experience, I’ve received them randomly from Portkeys. I’ve also seen them (less frequently) on the ground during some kind of event (Brilliant Event, Community Day, etc.). They still seem to be somewhat rare.
I’ve only ever gotten them from portkeys. I think it is a portkey only ingredient.
no, found it on the ground
I finally found 2 this morning. They were in the portkey with the big hand
I was wondering. I have opened 32 portikeys since it was released and nothing.
I Guess it is the Doxy of ingredients
I am now over 45 Portkeys, no Erumpent Horns.
Have they removed it from the game???
78 Portkeys no Erumpent Horns
I venture to say Niantic has removed Erumpent Horns from the game. I have not heard of anyone finding them in 10 days