Putting down a horse

Truly unique photo - not sure if the horse is sick or is being put down.

I believe that this photo was taken at a farm in Chico California.

This photo is one of many found in a series of old early 1900's Badger Gem family scrapbooks that were donated anonymously by a family in Green Valley Arizona. These photos seem to be of select areas including Southern California, Chico, Coronado San Diego, Long Beach Pasadena, Yellowstone National Park, Colorado, and the Continental Divide.

Who are these farmers and what are they doing to this horse?