Welsh cob grayscale

I had this lineart laying around for quite a while and found it to be a shame that I hadn't used it yet I was lazy though so I did a greyscale instead of one in full color. But now I have used the lines so I don't feel bad about that anymore  

Time: 2 hours with breaks (for the shading, approximately 2-3 hours for the lineart). 
Reference(s): Personal photos
Background: Personal photos
Layers: 3, background, shading, lines
Size: 4000x2950 (which was so unnecessary but it was the original size of the lines)