In my metro area, most of the acreages now have electric gates with a passcode. I think security on the other sides depends on your neighbors. My impression is that folks here “harden” the road frontage which can include a ditch, a big hedge, and the electric gate. Much of our rural areas traditionally had huge road side ditches that meant you could only enter by the designated driveway, but those are disappearing.
My impression is that horse folks don’t worry too much about hardening the other perimeters if they back onto other similar rural properties. If all the farms have good front gate security, and the property owners are responsible, all you need are good stock fences.
Things would differ if you backed onto s park, a public walkway, a housing subdivision, a school, or an empty lot or bad neighbors. In that case you’d want to think about strategically hardening that particular fenceline.
Honestly here in the PNW your best bet might be to let the Himalayan blackberries take over your fenceline. They will quickly produce a 20 foot tall mound of the closest thing to razor wire thatvnature makes. Plus they are edible to horses.
I would do a driving tour and see how all your direct neighbors manage their front gate security. I would look at Google Earth to see how the properties interlock. I would observe my neighbors and get to know them by name, see their land use patterns.
If your neighbors are halfway responsible small farmers they will respect fence lines instinctively and never want to get into your pastures. And anyone that sneaks into their property is unlikely to then sneak over to yours.
If you do want to harden the backside stock fences, electric wire is a great idea because people don’t like to mess with it.
If you do have crazy neighbors on one side, you can think about selectively improving that fencing.