All great suggestions, and I do have one base that I (after losing the entire farm twice) optimized the distance from the main compound such that I have them just in a basic fence, but I don't think that eliminates the risks entirely, since there are structures in the area that I use.

In other places I've had no problem building a "normal" looking fenced in enclosure that I've kept inside the walls of my compound. Events spawn outside the walls and normally I don't even concern myself with them. In that case I'll probably just combine all the animals together and hope for the best.

In this case, unfortunately, I just happened upon a 2* boar in a relatively small meadows that is surrounded by plains and mountain. I built a house while I tamed and cultivated them, planning on brining in some wolves and lox eventually. I haven't seen another boar of any sort in this sliver of meadows since, and the chances of finding a 2* is likely pretty close to 0, so I'll probably just abandon the place.

I find it a bit silly to have farm animals in a game that you can't actually have in a farm-like setting. Did they consider the effect that the bats would have before they introduced them? They add nothing to the game that I've seen, since they do no damage, yet they seem to have ruined the ability to have a normal farm.