I have been told that draft horses are slower matures that some breeds (like Quarter Horses for example). However, I have been told the opposite also. I have been told that they are fast matures and that they can be started under saddle at 6 months old!
I thought that was pretty insane.
So I thought I should listen to people who have actually dealt and possibly have breed draft horses and, from self experience, have trained one for under saddle.