Conventional wisdom holds that fences might make good neighbors but are not necessarily effective at keeping feral hogs and deer out of cropland.

An Auburn University Extension agronomist may challenge that assumption however, while admitting that no guarantees exist when it comes to keeping hogs or deer away from a banquet of tender young plants.

(For background on the problems being encountered in Alabama with feral hogs click here.)

A three-strand, high tensile electric fence offers a promising solution to devastating damage caused by hogs and deer in Alabama, says Richard Petcher, regional Extension agronomist in Washington County, Ala.

Petcher, speaking to the recent Southern Peanut Growers Conference in Panama City Beach, Fla., reports early results from a Mega Fence indicate a success rate in keeping deer and hogs out of fields as high as 99 percent.

The fence design for deer differs from the one used for feral hogs.

The deer configuration includes a three-strand, high tensile electric fence. Strand interval is 18 inches, 36 inches and 54 inches above ground. Three feet out from this fence is a one-strand high tensile electric fence 18 inches above ground. Posts are T posts spaced 50 feet to 60 feet apart. Outside posts are rebar placed 40 feet to 60 feet apart.

Fencing for hogs puts the lower wire 10 inches to 12 inches above ground and the inside fence only requires two strands, the lower at 10 inches to 12 inches and the top strand 24 inches high.

“The idea of two fences it to disorient the deer or hogs,” Petcher says. “They hit one fence and continue through, but the second fence gives them a second opinion and normally they decide it’s not worth another shock to eat a little corn or cotton.”

Petcher says spraying herbicides under the fence to kill weeds is important to prevent shorting out. “Having the fence row clean also allows the animals to see it and it presents a visible barrier.”

He says the fence should be plugged in as soon as the wire is strung. Also, chargers should have a high joule output and low impedance output.

“We need at least an 8-joule charger to deter wildlife,” Petcher says. “For fences covering more than one mile, use a 12-joule charger.”

He says solar chargers may be ideal for rural areas.

Cost for a mile of fencing, using a 12-joule charger would be approximately $3,000.That’s for a 40-acre field and does not include labor or corner posts. “T-post, corner posts are low in labor demand and are inexpensive,” he says.

He figures per acre cost is $75, but over three years that’s only $25 per acre, per year.

Petcher says farmers can build the fence during the winter months but should wait until just before or just after planting to string the wire. They take down the wire after harvest.

He says a few key strategies increase efficiency and efficacy of the Mega Fence:

• Field border preparation is important. Make borders as smooth as possible since deer and hogs will look for low places to go under the fence. Fill in ditches and other low spots.

• Timing is critical. Put the fence up the day after you plant. Current must be on when the fence is up. Deer and hogs are creatures of habit and once they break in they will continue.

• Once the fence is hot, check it the next day and the next. Deer and hogs will tend to break in the first night or two, so don’t neglect the fence.

• Keep the fence charged. And take it down immediately after harvest.

• Choose the correct charger with at least 8 joules and 12 for longer fences.

• All wires must be hot.

• The ground system is critical. Farmers need one ground rod for the box and one additional rod for each four joules of output: three ground rods for an 8-jule charger.

• Wire selection is important. Most growers use 12.5 to 14 gauge high tensile wire. Other wire may work but must be thick and strong enough so wildlife will not break it. It must be a good conductor. Stainless steel is not a good conductor. Polybraid rope with copper filament is a good choice—a bit expensive but easier to handle.

• Locking insulators help prevent wildlife from knocking the wire down.

“If you think you can completely fence out deer and hogs, think again,” Petcher says. “Building a fence that would stop all wildlife penetration would take more money than most growers want to spend.”

He says sometimes animals get through both fences but then are afraid to get back out. “Farmers can then ‘relocate’ them,” he says.

The fence performed well in several farm trials in 2009,” Petcher says, and an officer with the Alabama Department of Fish and Game monitored the system and rated the Mega Fence as having 99.9 percent control.

Farmers may adapt the idea to a pre-existing fence. Petcher says one farmer placed a single strand of polybraid cord 12 inches high and 12 inches out from an existing four-strand, non-electric barbed wire fence.

“He had counted 75 deer grazing in his soybeans. At present, no deer have crossed the fence.”

He says most deer rarely jump fences and, like hogs, go under them. “They get their first good shock when nosing under and do not come back.”

Petcher says wildlife accounts for $70 million in annual damage to Alabama cropland.

He says several companies may offer help with a Mega Fence. Farmers may contact Taylor Fence Company at (205) 594-5971 or http://www.TaylorFence.net; Powerflexfence at (417) 747-1230 or http://www.powerflexfence.com; and Gallagher Fence U.S.A. at (334) 654-0936 or http://www.gallagherusa.com.

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