Animal textures

While going down to check up on my wheat farm, I noticed that my horse and llama happened to appear red and green. I got on my horse and when I opened the inventory, it went back to normal. Just a couple seconds later it started doing the same thing as before and went back to the strange colors. I have no idea if it is doing the same with other animal mobs because my sheep seem fine. Maybe it was something to do with my texture pack, but my brother has had the same problem without any textures.