A yearling colt was one of three horses found dead near Sundre on Tuesday night. ((Courtesy Wild Horses of Alberta Society))

Police and wildlife officials are investigating the fatal shooting of three wild horses, including a pregnant mare, near Sundre, northwest of Calgary.

The animals were found Tuesday night near the Mountain Aire Lodge motel and campground west of the town, about 500 metres from a mountainside road, the RCMP said Wednesday.

It appears the horses were shot from the road late in the afternoon, police said. Evidence at the scene indicates that the mare went into labour after she was shot, said Bob Henderson, president of the Wild Horses of Alberta Society.

"For the first time in a long time, I actually cried this morning. It hurts your heart when you watch them out there, the way that they are and live out there. They're such a beautiful, magnificent animal, and to see this needless, senseless act just sickens the heart," said Henderson, who visited the scene on Wednesday.

The pregnant mare looked ready to foal within a day or two, Henderson said. A stud, about two to three years old, and a yearling colt were also found dead.

"He suffered a long, agonizing death by the look of the scene," Henderson said of the stud, who was found dead on his back with his legs in the air, tangled in some trees.

The deaths bring the total number of wild horses killed in Alberta to more than 22 over the last four years. The society is offering a $10,000 reward for information on the killings.

Anyone convicted of killing cattle, which is the category feral horses fall under, faces a maximum sentence of five years in prison under Canada's Criminal Code.

The Alberta government estimates there are about 300 feral horses in the Sundre area. Provincial biologists don't consider them true wildlife because they originated from domestic horses used in logging and mining operations in the early 1900s. Horses were often turned loose or escaped, leading to several generations of offspring that still live in the area. Other feral horses in recent decades may have been illegally abandoned by owners, according to provincial officials.