The investigation is continuing to unfold into the deaths of more than 100 wild horses housed in a Colorado holding pen. Officials probing an influenza outbreak say pneumonia in the animals may be complicated by inhalation of wildfire smoke and dust.
A report on the deaths of 106 wild horses said some of the wild animals were suffering from severe pneumonia and either died from respiratory distress or had to be euthanized.
The Colorado state office of the Bureau of Land Management is working to learn what killed 67 wild horses kept at its Canon City Wild Horse Facility, about 300 miles from Utah.
Colorado wild horses from two distinct regions died while in a wild horse holding pen in Canon City. Investigators say the infection is highly contagious and fatal, killing 67 of the animals. Officials are trying to determine what caused the deaths.