I've noticed this since the beginning but never got around to asking about it. I assume it's the same for PC and consoles, but because I play on PC I thought I'd ask here.

Does anyone else notice that as you're still a little ways from the horses, their mouths are wide open, and then when you get within a certain range/lod they suddenly snap shut? It's a small thing but it's always bothered me. If others have experienced this, can you explain why it happens and what, if anything, can be done about it?