Horses always change colors

Horses are always changing colors. They go from bright green and pink to red and white and this happens in less than a second when they change colors.  Before I even take them they change colors like that. This also happens with skeleton and zombie horses too.  It also does this with donkeys and mules.  I really want this fixed because my sisters are always happy with their horses because they get to see theirs and when I want to see what my horse looks like I have to wait until I can see through they colors or ask them if I can see in their kindle or tell me what it looks like. Please fix this as soon as you can.  Thank you so much.