FYI - also for what it is worth, breeding wolves and boars together in same pen seems to work, but they both follow the same distance rule, but with either species.

e.g. both sets will breed, but each seem to count the other as population in terms of stop breeding once too many in same pen. Had thought maybe wolves would only count wolves but if too many boars, then they stop breeding or vice versa.

ended up just making side by side pens with wolves in one, boars other, since there is no space savings by lumping both together.