Fencing In: Science Fiction

It was the fences that got people talking. Good fences make good neighbors and all that, but these fences were ten feet high and had barbed wire--pointed inside. Like prisons. Sure, the agricorp said that they had corporate patents and needed to protect their merchandise, but again--fences pointed inside? That was to keep something in. There were rumors about how it was to keep in animal experiments, pigs grown huge, not just fat, bulls large enough to knock down a house. Nobody really believed it. Not until they got out. First thing we knew of it was when something the size of a woolly mammoth rampaged down our street. Set off all the car alarms, broke the glass out of the car windows, and--

Inspiration: Glancing out my study window at my fence.
Story Potential: Medium.
Notes: It's like all those great/awful 60s horror movies. Night of the Lepus!