During Kentucky Derby Week, two horses mysteriously pass away, and two more are euthanized due to injuries.

Since the Kentucky Derby’s opening night, four horses have died. The deaths were described as “completely unacceptable” and “highly unusual” by Churchill Downs Racetrack, which hosts the crown jewel of competitive horse races.

“We take this very seriously and acknowledge that these troubling incidents are alarming and must be addressed,” Churchill Downs said in a public statement on Wednesday.

Four deaths during Kentucky Derby Week, which takes place every May in Louisville, Kentucky, have owners, trainers, and animal welfare activists asking questions despite the fact that thousands of horses have died from racing-related injuries in the past decade.

After winning races, two horses suddenly collapsed and died of unknown causes. A statement issued by Churchill Downs Racetrack stated that irreparable injuries necessitated the euthanasia of two additional horses this week. A horse can only win the Derby’s coveted Triple Crown, which includes a multimillion-dollar prize, if it wins all three races.

Parents Pride passed away on Opening Night, while Chasing Artie passed away on Tuesday. According to the statement, both horses were trained by Saffie Joseph Jr. and owned by Ken Ramsey. According to trainer Joseph Jr., the two horses appeared to collapse out of nowhere.

Two other horses sustained musculoskeletal injuries, which are bone and joint disorders that can cause debilitating pain and impair a horse’s ability to see, breathe, and even chew and swallow, according to Stephen B. Adams, a professor of surgery at Purdue University, College of Veterinary Medicine.

Wild Ice, one of the horses, suffered an injury during training on April 27, while Take Charge Briana, the other horse, sustained an injury in a turf race on May 2. Churchill Downs stated that both horses “were ultimately euthanized for humane reasons.” Wild on Ice was taken to Rood & Riddle Equine Hospital for treatment.

Each of the four ponies will go through complete necropsies at the College of Kentucky Veterinary Diagnostics Lab, the assertion said.

Churchill Downs and Ramsey Farms have been contacted by CBS News for comment.

Each of the four ponies will go through complete necropsies at the College of Kentucky Veterinary Diagnostics Lab, the assertion said.

Churchill Downs and Ramsey Farms have been contacted by CBS News for comment.