A second horse has died at Santa Anita Park since the beginning of the year

[Perseus]

2. I am going to demonstrate my ignorance about horses but...

How do we humans know that a horse might rather end his days fine with a broken ankle, just walking around the stable, eating grass and an occasional carrot or apple that the owners give them, with today's technology I have to assume the leg can be fixed enough to allow the horse to retire comfortably without any need to gallop in a race, or gallop at all?

I never understood why they have to be put to sleep, it kind of sounds to me that humans don't want the expense of keeping the horse any longer...I could be wrong, as I said, my ignorance about horses goes beyond normal.