reporter: several jockeys have also been injured and some nervous owners are pulling their horses off the grass track. for the last few years, the breeding of thoroughbred race horses have been more about speed than stamina. so you probably have overall a little more fragile a horse than you have had in the past. reporter: the turf course is now shut down as track officials try to soften it with water. in your expert opinion, is this track safe? yes. i believe so. reporter: del mar also has a synthetic track that is supposed to be safer and soft other a horse s delicate legs, but three horses have also died on that track. it s unclear whether any of these deaths are connected or simply a coincidence. but racing watchers say they do mean a public relations nightmare for the racetrack. if you re bringing your kids to the track, you certainly don t want to see the trauma and the horror of a horse dying or being put to death out on the racetrack in front of you. reporter: d