Martellus

I haven't seen them yet on our server. I went back thru my posts to make sure I didn't said something that could suggest otherwise. The discussion was that all Unicorns found were females, and I inquired if anyone had a male to prove the breeding theory. Like yourself, we are incredibly curious if they can be successfully bred, which would be awesome for  other tribes.

As far as the discussion went, nobody had a male yet. 

According to this thread (further below), once a Unicorn is tamed, a new wild one should be spawned, which is weird as I understood only one could exist regardless of its wild vs tamed situation. Also, they say that a Unicorn only breeds with another Unicorn. Please view link: https://steamcommunity.com/app/346110/discussions/0/133261907147355622/

As for the thread I participated on the Unicorn discussion, Harrist14 posted a video which I haven't seen in its entirety yet, but claims to have bred Unicorns, I have skipped some parts and they do breed two unicorns, its just not very clear how they got the pair.

Hope this helps, sorry for the delay in my response. Cheers!