They look good, the next step is to start adding some detail. You have the basic shapes right, but if you start giving it more of the "sketching" look and start with shading and such like the person above said, you could really make some good improvements!
The legs look good, I think you need to maybe make the hooves a little bigger? Or look at the shape more carefully. Much better than I can draw though. (I only draw stick people and stick horses) haha
A horse is the projection of peoples' views about themselves--strong, powerful, beautiful--and it has the capability of giving us escape from our mundane existance.