Those wings are incredible. The shadows are so delicately rendered! The texture is perfect. Interestingly, the fact that the horse is not quite as closely rendered works because it does not compete with those wings.
I love this! You've incorporated the beautiful feathers and the angle of the wings perfectly into the forms and contours of the pony. And I love those blues you used as ambient lighting in some of the shadowed areas on the wing ^^ Very moody.