In America it seems totally normal to back horses at 2. Here (UK) we usually wait till they are rising 4 or later (apart from race horses as far as I know). What are these ages based on? Do we just assume that what we are used to is the right way?
I know a lot of famous racehorses lived to good ages before they crossed the rainbow bridge.... but how many don't?.
But in the USA they are backed at 2 and ridden 'properly' from that age, all the time.
Surely if this was catastrophic for them, trainers would have changed what they do.
But he often starts colts at 2. Yes they are ridden Western style, but why should that make such a difference to whether the horse is ready?