Drawing Horses from Life - Chase

I don't know how Degas and Toulouse-Lautrec did it, I guess they were around horses all their lives and there were no cars then but these critters are a real challenge for me.
These sketches are of Chase who is a magnificent beast, a 4 year old Clydesdale Thoroughbred cross and I am determined to get some good woodcuts and etchings of him from drawings done from life, right there in the paddock and not from photos.
I've tried photographing him and it's as hard or harder than drawing him strangely enough.
Horses seem to be worse fidgets than even me and believe me I am a wriggly restless creature.
My choice though and it's kind of fun when the big boy comes over and tries to eat the sketch book.