Welded wire fence.

This type of fence can make great horse fence, BUT it must be tall enough AND must be topped with an electric wire, or better, a wood plank, to prevent horses from "riding it down" as you can see has happened here.

The openings in the fence are small enough that hooves cannot fit through. This fence is typically used for chicken runs, goats and smaller livestock, so make sure the height of the fence is adequate.

The other problem you will run into with this type of fence used for horses, is securing the bottom of the fence to prevent horses from reaching under it, WITHOUT creating a dangerous possibility of hoof entrapment.

Barbed wire, again.

Only unsafe if you consider losing an eye a bad thing.

As the owner of a one-eyed horse (cause having nothing to do with fence issues) I can tell you it is most interesting, and I wouldn't recommend it.

Barbed wire, loose and low.

These two look like pretty nice horses, from what I can see.

Why on EARTH are they kept in too low, too loose, too dangerous fence?

Metal pipe fence.

Metal pipe fencing has many fans. Properly installed and maintained, it is considered one of the safer options.

While I'm not the biggest fan of it, I also have never used it or been at a farm where it was the primary fence type, so I'll try to reserve judgment.

As with all fence, maintenance is as important as installation. Care must be taken to prevent rust and watch for bends that could turn into cracks and exposed sharp edges.

Barbed wire over heavy gauge high tensile wire.

Oh, poor sweet face. This pony is saying, SAVE ME!

What happens when that blanket gets good and stuck on a few flesh-ripping barbs?

There ARE alternatives.

Traditional wood rail fence.

Time tested, properly installed and maintained wood plank fencing is superior to most types of fence available. The high cost, however, keeps many horse owners at bay.

You'll see plenty of wood fenced pastures in the communities with big money horses, and for good reason: it is probably the safest fence available.

Strong and highly visible, works in all weather and without electricity.

Small diameter electric twine fence.

This looks like either a very lightweight electric rope fence, or a possibly coated high tensile wire.

Either way, while superior to plain wire, and FAR superior to barbed, the visibility is not as good as properly installed electric tape, thicker braid or other non-electric visual deterrents such as wood or synthetic plank.

Fencing like this should be marked with brightly colored flags every 10-20 feet to increase visibility. Running, bucking horses forget that they "know" where their barriers are.

Electric tape and/or twine fence.

What exactly IS keeping this horse in, anyway?

Even if this is a quality tape fence on the bottom and a good plastic/wire combo thin braid rope fence on top, with electricity, the fence is too low for the horse, inviting a jump if spooked or otherwise motivated. (Perhaps by the green grass on the other side.)

Proper installation is key to making the safer types of fence as safe as possible.

Braided or "rope" fence.

Braided or "rope" fence infused with metal wires and charged with a good electric fencer is far superior to barbed or plain, uncoated wire.

Proper installation is essential; not too much space between posts, tensioners used to keep the fence taut, etc.

Visibility is superior to plain wire, but not as good as wood or synthetic rail.

Sagging woven wire with uncapped T-posts.

This may be one instance where the barbed wire is actually HELPING this fence to be 1% safer, but this is still an accident waiting to happen.

If the openings in a fence are large enough to allow a hoof to pass through, even the laziest horse can become stuck by a stray kick at a bothersome fly.

Fence that is not tight, sags and has broken in places adds immeasurably to the risk. If the fence were tighter and a hoof went through, the horse might be able to pull it back out, BUT if the fence "gives" because it is not tight, it is more likely to become entangled.

T-posts without protective caps can impale a frightened, fleeing horse.