In the lush, emerald hills of New Zealand, a childhood prank leaves young Henry Oldfield with a debilitating phobia of sheep and the weight of his father’s accidental death. Fifteen years later, Henry returns to the family farm to sell his share to his older brother, Angus, unaware that Angus has transformed the estate into a laboratory for reckless genetic engineering.

Black sheep is a New Zealand film about a farmer who's been conducting genetic experiments on sheep in a weird breeding programme, Black Sheep (2006) directed by Jonathan King - Letterboxd

: Forced to face his worst nightmare, Henry must overcome his ovine-phobia to survive the slaughter.

: A young activist who joins forces with Henry to stop the infection from spreading beyond the farm.

The story culminates in a desperate stand at the farm's main villa. Henry and Experience use everything from sheep-dip chemicals to a motorized shearer to fend off the horde. In a final ironic twist, the very phobia that crippled Henry becomes his greatest asset, as his heightened survival instincts allow him to outmaneuver the beastly Angus.

The infection is eventually contained when the mutated flock is lured into a pit and destroyed, though the final shot suggests that the genetic nightmare may not be entirely over. Black Sheep (2006) - IMDb

An experiment in genetic engineering turns harmless sheep into bloodthirsty killers that terrorize a sprawling New Zealand farm. Black Sheep - Pecore assassine (2006)