Sheepherders for the Siddoway Sheep Co. heard the wolves at about 1 a.m. Saturday, but didn't know the extent of the damage until they saw the sheep piled up on each other at daybreak.
J.C. Siddoway of Terreton says almost all of the sheep died from asphyxiation. About 10 died of bite wounds and one was partially consumed.
Idaho Wildlife Services State Director Todd Grimm says it's the greatest loss by wolves ever recorded in one instance in the state. About nine years ago, wolves killed 105 sheep on one night.
Grimm says a dozen wolves have been removed from the Pine Creek area this year.