I have 2 Lox paddocks, and they do indeed wander further and further away from where they are tamed...I have to round them up and drive them back to the paddock areas. It is a pain to retrieve them, wish after taming they would not pursue when aggro'd.

I made a concerted effort to make as many saddles as possible and that way I can just hop on and marshall them up where I need 'em. I jump from Lox to Lox and use my Ride skill to level up quickly....helps. Get some saddles made, asap, to keep them under control.

Without having the advanced gear to squat in the Plains, I would suggest tossing a ton of cloud berries near your stock and only visit occasionally to increase the herd...to offset any losses due to events, etc...they will stay near where they are when despawned when you leave the area and come back.