I have done a bit more research into horse anatomy and did some quick sketches on photoshop which show two of the most prominent muscles on a horses body - the chest and the top of the leg.

CHEST:

LEG:

I also had some of the final piece horses i had already finished printed out so I could see what they looked like away from the computer screen. I kept their white backgrounds at this point so it would be easier to see if the colours/contrast had come out as I had hoped.

I could also use this A2 print out as an example of my work when I am at an equine event with my trade stand for my sideline business of drawing people horses and dogs.