From the chest and markings, I'd guess erectus, but you don't really ID horses from the depth of their chest or their markings.... People would really need to see a nice full length profile shot, along with a close up of the head and one of the cornet (top of the head.) Photos have to be clear to be helpful (and, although it may seem as though your horses don't move a lot, they always seem to move when you want a clear photo.)