I’m wondering about getting horses to fall down in violent fashion. I can see a horse being trained to just roll over and act dead, but in many movies it seems horses are falling forward while running forward or in some other fashion that doesn’t seem comfortable or trainable (since animal instinct to avoiding harm is probably greater than the desire to get a sugar cube reward or whatever).
Decades ago, they used to tripwire horses for movies. A particularly infamous technique was called the “running w”. These days, yes, they might use specially trained horses. Apparently you CAN train a horse to fall over on command:
Looks like you also pull his head around, away from the direction you want him to fall, so he’s off-balance. Then you sort of pull him over while simultaneously adroitly slipping out of the saddle yourself and rolling away from him.