"under the fence" is a correct and usable part of a sentence in written English.
For example, you could use it in the sentence "The lost dog was found cowering under the fence."
It may be fenced in, but it's snarling, always trying to dig under the fence.
Carl dug under the fence between the two houses & stole a meal bowl.
Soon we're near the reservoir, and we squish ourselves under the fence.
Are there any overhanging branches or roots sneaking under the fence?
"It was fine until two little chickens started sneaking under the fence.
Carl dug under the fence between the two houses & stole a meal bowl..
Aha! Could something like that trim the grass and slash the weeds around the trees, between the rocks and under the fences?
But despite what appears to have been a slow crawl through the defenses (the three had bolt cutters, hammers, flashlights and cans of spray paint, and went under the fences), they did not draw a prompt response.
For me, Silverstone will be forever associated with the sunwashed day in July 1958 when, as a teenage schoolboy on the loose from Stowe School, two and a half miles across the fields from the Silverstone corner that carries the school's name, I burrowed under the fencing surrounding the track and made my way, eluding what little security there then was, to the pit-paddock area.
Make sure that the chickens cannot get through the fences and no predators can get in or under the fences.
Follow these guidelines to make sure the rabbits can't jump over or dig under: Bury the fence 4 6 inches (10 15 cm) deep.
