Second outbreak in Montana this year.
This is near an area where domestic sheep have been grazed to control weeds during recent years. The New York Times wrote a story about it here.
FWP kills seven bighorn sheep after pneumonia confirmed in Bonner herd. By Rob Chaney of the Missoulian
1-16-10 5 more bighorns killed in West Riverside in effort to stop pneumonia. By Rob Chaney. Missoulian