If you have a gap in your work bench coverage an enemy can spawn inside your base There might be a grayling running around inside. If you have an earthen berm around your base a troll can throw rocks over it. They target livestock first (including bee hives) then target crops.

Even if you have adequate work bench coverage things can still occasionally have creatures spawn inside as you can see here.
https://steamcommunity.com/sharedfiles/filedetails/?id=2860289081

To keep monsters off of your live stock you can build a barn to keep them in and if you hear squealing you can go check on the boars. The boars will be frightened and squeal even if they can't see or be seen or reached by the monster.
https://steamcommunity.com/sharedfiles/filedetails/?id=2853688746

If you neglect your boars they can die of starvation.